engine problem (chk eng lite on)

Greeting to all, I have a 2k montana with 181K on it. I have had no major problems except this problem that has started to occurr within the last 6 months. The problem is or feels like a tranny issue, it seems to only happen when the vehicle is in overdrive. It also seemed to only happen in the 1500 - 2000 rpm range, it seemed like the tranny was hunting from 4th gear to 3rd gear and back to 4th gear. Step on the gas a little harder, problem goes away. More noticeable on slight inclines with a load, family etc. This started in the summer, still happens in the winter, so not a hot or cold problem, just getting worse. It finally got so bad I took it in, the codes showed "long shift" and an "O2 sensor" problem, my local mech. phoned mr tranny and told him to clear the codes and all will be well, worked great for 3 months then started to go down hill again. It got so bad that even cruising at 60km/hr problem was evident. Took it into Mr. Transmission and the guy had it for 3 hours and said it is not the tranny, he could reproduce the problem by holding down the brake and he called it "engine lock down" or "lock up" something like that. He tells me to take it to local mech. again.

Take it to local mech. they can reproduce the problem, codes say it is mass flow air flow sensor, local guy tests that sensor and it passes, he does not want to change it since it is $300 to replace. thank you., the guy drives around and it is still failing, he clears the codes and all of a sudden he cannot reproduce the problem, I get it back, next day same problem...now I am upset. It is really cold out and the problem manifests itself and am willing to take it to the dealership and make them accountable for the problem. I drive home the next day, and then the check engine lite goes off and everything it golden.

Has anybody ever experienced this, I have searched and searched and not found anything, I have read tons of forumns and same deal. I think it could be a computer module, it probably would cost a ton ....any ideas would be appreciated.


thanks,

I think you're on the right track to suspect the computer module (PCM). While I haven't had problems like this with my van (98 Venture, 90k), I have had similar problems with my 89 Cav Z24 (2.8L V6).

Long story short, the computer module does a good job of monitoring your sensors etc for problems, but a very poor job of finding problems with itself. The first time it happened to me, I swapped out about $1000 worth of parts before a senior tech suggested that I might try the computer. By this point, I'd tried just about everything else, so I bit the bullet and swapped the module - problem solved!

I think you've had good advice to this point - nobody has swapped a good part in the blind hope of solving the problem. My experience is that if it's a head scratcher that no-one can solve (and it sounds like you've had good people looking at it) then it's probably the PCM.

Hope this helps....

B

One further note - with the car, turning the vehicle completely off (to the point of pulling the key) reset the computer, and often solved the problem (in the car the problem was a racing idle/stalling). If your van starts acting up, try this a few times to see if it makes a difference. If this works on the odd occasion, I'd all but guarantee it's the computer.

B

Look out.. Not being an expert, but this sound like how my problem (posted under thread Oil cap or PVC valve) started this summer. When I was cruising at highway speed it felt like the transmission was jumping/shifting or maybe an ignition problem. Check engine light turned on randomly. My local mech looked at transmission (=fine) and checked ignition and changed sparkplugs (those were getting too old). Unfortunately this problem has developed to that the engine dies when idling, randomly... It only happens when the engine is warm, randomly... and usually gets worse if I have started and stopped the car often, randomly. My local mech is out of ideas - and so am I. I guess the central computer can be it.

Greeting to all, I have a 2k montana with 181K on it. I have had no major problems except this problem that has started to occurr within the last 6 months. The problem is or feels like a tranny issue, it seems to only happen when the vehicle is in overdrive. It also seemed to only happen in the 1500 - 2000 rpm range, it seemed like the tranny was hunting from 4th gear to 3rd gear and back to 4th gear. Step on the gas a little harder, problem goes away. More noticeable on slight inclines with a load, family etc. This started in the summer, still happens in the winter, so not a hot or cold problem, just getting worse. It finally got so bad I took it in, the codes showed "long shift" and an "O2 sensor" problem, my local mech. phoned mr tranny and told him to clear the codes and all will be well, worked great for 3 months then started to go down hill again. It got so bad that even cruising at 60km/hr problem was evident. Took it into Mr. Transmission and the guy had it for 3 hours and said it is not the tranny, he could reproduce the problem by holding down the brake and he called it "engine lock down" or "lock up" something like that. He tells me to take it to local mech. again.

Take it to local mech. they can reproduce the problem, codes say it is mass flow air flow sensor, local guy tests that sensor and it passes, he does not want to change it since it is $300 to replace. thank you., the guy drives around and it is still failing, he clears the codes and all of a sudden he cannot reproduce the problem, I get it back, next day same problem...now I am upset. It is really cold out and the problem manifests itself and am willing to take it to the dealership and make them accountable for the problem. I drive home the next day, and then the check engine lite goes off and everything it golden.

Has anybody ever experienced this, I have searched and searched and not found anything, I have read tons of forumns and same deal. I think it could be a computer module, it probably would cost a ton ....any ideas would be appreciated.


thanks,

First off, why are you going to hold the dealership accountable for your problem?
Did they send a top secret gamma ray out to disable your vehicle causing you to have to take it to them?
Just because you haven't shown any loyalty to the dealer, doesn't mean they have to show loyalty to you.
I can pretty much guess you haven't been to the dealer since your vehicle went out of warranty...and then you only got warranty repairs done and probally never spent a dime with them to have your vehicle serviced.
The codes are an indication of what the problem is..It takes a Technician with knowledge and experiance to decipher the information and fix the problem.

I agree with Merlin! We do not go around breaking your car how can we be accountable for what your car does or doesn't do? If you want to guess take your car to a mechanic want it fixed take it to a technician!

And what have you done to your car? Could you be the cause of your problem? Do you use KN air filters, do you use remote starters?

While I would agree that a dealership "shouldn't be made accountable" for any problem, personal experience shows that the dealership doesn't necessarily possess the magic bullet to solve all problems either.

As consumers. we are well aware that dealer shop rates are generally the highest of anybody, so you can't blame us for taking our cars to shops with lower rates. It sounds to me that both Merlin & Flatrater are trying to tells us that only GM can fix our cars - which means we're being held ransom by GM.

So, you take exception to our "blaming" GM or the dealerships for the problems that we have, but you don't seem to have a problem with us being forced to pay top dollar to get our cars fixed.

Many of us that hang out here are amateurs - we like to do things ourselves, learn how our cars work and save a few bucks in the process. We're quite familiar with the "genuine GM parts" propoganda, which has recently been expanded to include "genuine GM service". You guys are paid to buy into this crap - we're not.

But don't get us wrong: we appreciate your hanging out here and offering us advice. Just not as GM representitives. I do observe that your 30 years of combined experience hasn't offered anything constructive to this thread - just anger at us not buying into the corporate propoganda that is a conditon of your employment.

Chances are, most of us live hundreds if not thousands of miles from where you work. So we don't have the option of paying you personally to work on our cars. If you'd like to help us fix our cars, that's great. But don't tell us that we have to go to GM every time we have a problem, we don't like that. It's that kind of thinking that makes us think that GM should be accountable for what goes wrong with our cars....

BA

Let me answer this point by point.
1.While I would agree that a dealership "shouldn't be made accountable" for any problem, personal experience shows that the dealership doesn't necessarily possess the magic bullet to solve all problems either.

GMM..At no time did I say the dealership is the magic bullet. The dealer I work for has 18 people working in the service department as "technicians" of those;
8 are ASE Master Technicians
4 of the 8 are GM Master Technicians
1 of the 4 is a GM Master Technician in more than 1 specialty.
So that means that less than 50% of the people employed are "certified" to work on your car.


2. As consumers. we are well aware that dealer shop rates are generally the highest of anybody, so you can't blame us for taking our cars to shops with lower rates. It sounds to me that both Merlin & Flatrater are trying to tells us that only GM can fix our cars - which means we're being held ransom by GM.

GMM...It is a free society, you have the right to take your vehicle anywhere you want to have it serviced and repaired.
If you read my reply to this thread, I said a Technician can repair your vehicle. In no way did that say a GM Technician..but someone who has the training and knowledge to fix your vehicle.
Flatrater and myself are Technicians, who just happen to work for GM dealers.
We have access to an unlimited supply of information from GM, plus we have the ability to discuss specific problems through a GM tech forum and a technical assistance network.

3. So, you take exception to our "blaming" GM or the dealerships for the problems that we have, but you don't seem to have a problem with us being forced to pay top dollar to get our cars fixed.

GMM...It seems like the going thing to do here on this forum..blame the dealer..How would you feel if I bashed your profession or employer and in the same breath asked you for help?
I read post after post from people who say they have had their vehicle to every mechanic in town, spending 100's of dollars on "repairs" on their cars to avoid spending 80 dollars at the dealer.
I have personally seen receipts where people have spent 200 dollars at Jiffy tune and Precision lube on repairs to their cars that would have been covered under warranty at the dealer or there was a simple fix outlined in a tech bulletin that would have resulted in a repair bill of less than 100 dollars.
Also take in account that being a mechanic or technician requires a huge investment of your own money to purchase tools to perform the job. (a common misconception by the public is that the dealer or employer supplies our hand tools..."automotive urban legend")
In my case around 50k just for the tools at work. Not 1 dime has come out of the employers pocket to help with tool purchases, but the employer reaps the benefit.
How many people have that kind of investment to make someone else money.
We as technicians don't set the labor rate or labor times.


4.Many of us that hang out here are amateurs - we like to do things ourselves, learn how our cars work and save a few bucks in the process. We're quite familiar with the "genuine GM parts" propoganda, which has recently been expanded to include "genuine GM service". You guys are paid to buy into this crap - we're not.

GMM...I have worked on many a vehicle with aftermarket parts installed that have made the problem worse. I believe in using parts that are specifically designed for the vehicle being repaired.
I do have more leaway at my own shop to use more "cost effective" parts when doing repairs. I do recommend GM parts specifically during some repairs because I know their reputation and have had problems with aftermarket parts in the same situation.
I do try to educate my customers and respect their wishes if they wish to use the more "cost effective parts"
I commend you and everyone else here for taking time to learn about your cars. There is a sense of accomplishment when you can say "I fixed it myself"

5.But don't get us wrong: we appreciate your hanging out here and offering us advice. Just not as GM representitives. I do observe that your 30 years of combined experience hasn't offered anything constructive to this thread - just anger at us not buying into the corporate propoganda that is a conditon of your employment.

GMM...I am not a GM representive. I am a car nut just like everyone else here.
I joined this forum to offer assistance to anyone who asks. I have supplied GM technical information, repair information and warranty information...If you feel that you do not need that information, then I can "take my toys and go home"
I also have refered people to avenues of recoarse when they have not been satisfied with the dealer and have tried to inform those who repeat the "automotive urban legends" about dealers.
I do get sick of the "Dealer Bashing" and the "Stealership" comments. Myself and others are dealer employees and have tried to assist members of this forum in finding satisfaction with their automotive needs.
We may be in the minority, but we take pride in our work and dealers.
We have hundreds of hours of training every year to keep up with technical and model changes.
You are getting the 80 dollars of diagnostic time for free.

6.Chances are, most of us live hundreds if not thousands of miles from where you work. So we don't have the option of paying you personally to work on our cars. If you'd like to help us fix our cars, that's great. But don't tell us that we have to go to GM every time we have a problem, we don't like that. It's that kind of thinking that makes us think that GM should be accountable for what goes wrong with our cars....


GMM...I would love it if I could prove to you personally the quality of mine and the other Master Technicians work here at the dealer I work for or the dealer Flatrater works for.
I know Flatrater and his desire to be the best Technician he can be, We are on a first name basis and even though he lives 600 miles from me, I consider him a friend, brother and 1 hell of a tech!
I never tell anyone they have to go to the dealer to have their vehicle repaired..I have recommended it because I know the dealer has the technical information, product knowledge and special tools to perform some repairs that you or independant repair facilities do not have.
Sometimes cheaper is not better.

I think you guy's took my post a little too personally, first off, I have taken the car to the dealer for everything, I mean everything, oil changes, tranny service, by the book, I use my car for business purposes and do not mind paying a little more for service, since most of the cost I can use for tax credits. I have never had any major problems with this vehicle. My meaning of accountability was meant to say that if it was in for service and not fixed correctly then they are responsible to fix it again taking in account that the part they replaced and charged me for was taken in account. Can you honestly tell me that you have never changed a part thinking that it fixed the symptom and only find a week or so later that the same vehicle was in for the same problem. Do you charge the customer for that part ????

As an update to the car, it was chuggin along doing the same thing and I was getting upset at bunny hopping along the road when, the chk engine lite went off , this has never happened before, the codes always had to be cleared and now the car runs perfectly. who knows !!!!

If I may jump in here, my 2001 with only 21K miles on it experiences the same symptoms at times.

It happens usually when I'm starting to go up a slight incline and I haven't given it more gas yet. When I start to slow down because of the incline, the tranny goes to the lower gear, then back up, then lower again. Giving it more gas to force it to stay in the lower gear makes it go away.

The van is still under warranty (bought in April '02), so I may bring it in to the dealer and see what they can do.

-Ax

I too have a problem with a check engine light and a transmission code on a 1996 Beretta z26. The transmission code started coming on shortly after I had a new transmission installed. The light was the only symptom. The shop checked everything over nine ways to sunday and found nothing. The cleared the codes and asked me to drive it and see what happened. Every 1000-2000 miles the check engine light comes on with a transmission code. The shop has replaced the transmission twice more. The solenoids, hoses, connectors etc have all been checked and rechecked. Everything appears to be fine except for the check engine light. Any suggestions? Is this a prime candidate for a pcm glitch?

If I may jump in here, my 2001 with only 21K miles on it experiences the same symptoms at times.

It happens usually when I'm starting to go up a slight incline and I haven't given it more gas yet. When I start to slow down because of the incline, the tranny goes to the lower gear, then back up, then lower again. Giving it more gas to force it to stay in the lower gear makes it go away.

The van is still under warranty (bought in April '02), so I may bring it in to the dealer and see what they can do.

-Ax

I would be real interested in finding out the problem, since yours is still under warranty let me know ....thnks

I think you guy's took my post a little too personally, first off, I have taken the car to the dealer for everything, I mean everything, oil changes, tranny service, by the book, I use my car for business purposes and do not mind paying a little more for service, since most of the cost I can use for tax credits. I have never had any major problems with this vehicle. My meaning of accountability was meant to say that if it was in for service and not fixed correctly then they are responsible to fix it again taking in account that the part they replaced and charged me for was taken in account. Can you honestly tell me that you have never changed a part thinking that it fixed the symptom and only find a week or so later that the same vehicle was in for the same problem. Do you charge the customer for that part ????

As an update to the car, it was chuggin along doing the same thing and I was getting upset at bunny hopping along the road when, the chk engine lite went off , this has never happened before, the codes always had to be cleared and now the car runs perfectly. who knows !!!!

Dude I was almost ready to believe you until I reread your original post.
I read this:
"It finally got so bad I took it in, the codes showed "long shift" and an "O2 sensor" problem, my local mech. phoned mr tranny and told him to clear the codes"
And
"Took it into Mr. Transmission and the guy had it for 3 hours"
Oh yea this too:
" He tells me to take it to local mech. again.

Take it to local mech. they can reproduce the problem"
And then you finish with this:
"It is really cold out and the problem manifests itself and am willing to take it to the dealership and make them accountable for the problem"

So when you made this statement ..."first off, I have taken the car to the dealer for everything, I mean everything, oil changes, tranny service, by the book,"..that was not the truth.

So don't Piss on my boots and tell me it is raining.....I have a pretty good Bullshit detector!

Like I said before, the codes are an indication of what your problem is.
If the fault self corrects or passes the PCM tests after so long, the light will turn off, but the codes will still remain.
You have not given us a list of the code numbers...With the code numbers, a technician can use charts and schematics to diagnos the problem...with an intermittant problem, it could be caused by a connection or wiring issue, a temperature sensitive sensor problem or a faulty PCM.
Also with the code numbers, a technician can check for technical bulletins that may apply to your concern.

If I may jump in here, my 2001 with only 21K miles on it experiences the same symptoms at times.

It happens usually when I'm starting to go up a slight incline and I haven't given it more gas yet. When I start to slow down because of the incline, the tranny goes to the lower gear, then back up, then lower again. Giving it more gas to force it to stay in the lower gear makes it go away.

The van is still under warranty (bought in April '02), so I may bring it in to the dealer and see what they can do.

-Ax

Since your vehicle is still under warranty, take it back into the dealer.
There are a couple GM technical bulletins regarding trans shift/slip issues that may apply to your vehicle..

iamthesanman- If this is a tranny issue, 180Kmi+ on a 4T65E is about all your going to get, and actually your lucky to have it last that long! Be happy you made it that far! You could push 200Kmi+ with an EXTREMELY light foot, 12-20Kmi ATF changeouts & almost all highway miles.
G/luck
Joel

My van has the same slipping? tranny too and also has hard shifts at times. Only 58km but out of warranty. It will only happen in overdrive while going up an overpass or slightly easing on the gas on level pavement, press harder and it goes away. I've driven in 3rd gear and it has never happened. Took it to the dealer and they ran the code...P1811. They said it needs a trans shift solenoid and possible valve body, $1200 parts and labour CDN...Nice!! Took it to a tranny shop for another opinion, they dropped the pan and said there was alot of brass fillings in it. Thought it might be the converter but wouldn't really know until they dropped the tranny. GMMerlin any opinions???

Just recently the van has had the check engine light come on due to the van stumbling when accelerating. This doesn't happen very often, only twice and the light doesn't stay on, maybe a day. Haven't had time to go get this one checked yet. Dam van!!

Just a heads up from someone that HATE's working on cars. I have had the same problems, listed above, poor performance, engine hesitation, engine light on, etc....

I tok the time to take it to a local repair chain who told me $300 to replace the MAF. I spoke to ASE certified friend who told me I could do it myself!

In denial, I bought the part anyway with the intention of paying him to do the work instead.

When I opened the box I wanted to slap myself, I couldn't believe this was the part! The MAF sits right on top of the engine next to the air filter & the MAF is actually easier to replace then the stupid air filter!

To anyone reading this thread, save yourself some grief & some cash & replace the thing! It cost's $114.00 (in Chicago) & takes 10 minutes to swap out! How much are you willing to pay in towing & repair costs if it goes out during a summer trip (god forbid the look the wife will give you)?

Franklin Jackson
Zenubian@yahoo.com

My Venture had a similar problem. The tranny did not slip, but it had intermittant hard, jerky shifts. If you shut the engine off, it would go away. The check engine light came and went often. I finally let the dealer rape me for $70 to read the codes, showing mass airflow sensor and a couple tranny codes. They wanted $225 for the MAF sensor, and $2000 for a new tranny, not counting labor. I went to my local Autozone, purchased a MAF sensor for $104, installed it myself, and the transmission has not jerked since (over 1 month now). It did it almost daily, before. The check engine light never did come back on, either. I don't know if any of this applies to your problem, but I thought I'd share my experience.

Look out.. Not being an expert, but this sound like how my problem (posted under thread Oil cap or PVC valve) started this summer. When I was cruising at highway speed it felt like the transmission was jumping/shifting or maybe an ignition problem. Check engine light turned on randomly. My local mech looked at transmission (=fine) and checked ignition and changed sparkplugs (those were getting too old). Unfortunately this problem has developed to that the engine dies when idling, randomly... It only happens when the engine is warm, randomly... and usually gets worse if I have started and stopped the car often, randomly. My local mech is out of ideas - and so am I. I guess the central computer can be it.



Have you tried changing the fuel filter?
Might be a good place to start.
Just a suggestion
Davey Carpet

I am having a similar issue as well. Has anyone had this resolved?

Yes, as in my earlier post, no problems of any kind since replacing the MAF sensor.

KJRich, when you say jerking shifts, you're referring to like the 1-2nd shift and others on up are smoother right? my tranny doesn't slip, but does have harsh shifts from time to time. The other day while on a long road trip my SES light came on, and autozone said it was MAF. I had them reset the code and haven't seen the light since (about a month ago). It also seems to buck pretty good when putting it into drive or reverse. I'm hesitant to replace the sensor since i'm already about to fork out for intake gasket set (dealer says 6-7 hundred)
And also, i'm wondering if since MAF code usually comes with tranny codes, could this be why my van seems to shift at a higher speed (20-25MPH) than most cars?

Mine jerked every shift, 1-2-3-4. It came and went. When it started jerking, if you stopped and shut the engine off and then restarted it, the jerking would go away for a while. I had this problem for over a year until I finally replaced the MAF sensor. I took it to the dealer and got MAF and transmission codes. They wanted to replace the tranny for $3000+. I talked to some people online and they said try the MAF sensor first, since everything is inter-related with the engine computer. I can't guarantee you it will help your problem, but it is something to think about. For me it was worth spending $105 (there will also be a core charge for the old sensor) to try to fix the problem. If that hadn't fixed it, I found an independant transmission shop that could have fixed the tranny for a couple hundred dollars, or I was also considering trading the van in.