When driving on slight incline with steady throttle between 50 and 65 mph Have shudder, let up or increase gas lightly, shudder goes away. had Dealer look at it four times. They can't find the problem. I heard it might be a PCS (pressure control solenoid). Or PCM (powertrain control module) Feels like car is skipping or missfiring ,but checked all electrical and plugs wire, etc...
Any Ideas out there?

Was your Service Engine Soon light on? If so, did the dealership get any codes and what were they?

No engine code lights.
The problem only appears when you are in overdrive and the engine rpm is low and you are going up a grade or slight incline in the road. If you hit the brake and let the car come out of overdrive the problem disapears.

I have the same problem, LS model (3.8L) Regal.

The problem got slightly better when I changed the fuel filter. Then it didn't happen quite as often, but continued, nonetheless as you describe - increasing the load slightly when cruising.

I'm stumped, too.

I just changed the fuel pressure regulator (a $50 item in the fuel rail) thinking the regulator spring might oscillate or resonate under certain conditions.

It seems to be a fuel delivery problem - surging. The frequency is always the same, about twice per second. The tachometer reflects the surging, indicating it's not a transmission slippage problem.

This is fairly common. It is th car trying to get the best MPG. The TCC locks up then the RPM's drop causing it to release. It will feel like it is "shifting" up and down. Almost all cars nowadays do this to some degree. Different cars will do it a different times and speeds due to HP and useable torque being different. The tach IS indicating the change in RPM's. This is NOT a fuel related problem. This is a design issue on almost all newer cars due to the CAFE (Corp. Average Fuel Economy) rules. The dealer won't notice the problem because to them it is "normal". Advise them of what I have told you and you may be able to have the dealer change the programming on the PCM so that it locks up a little later. Good Luck.

My 94 Reagl (85,000 miles) has just started doing this too.
THIS IS NOT NORMAL!

I believe the problem is in the transmission or in an electrontic component of the transmission.

If anyone else has had this and fixed it - please reply.

John

When driving on slight incline with steady throttle between 50 and 65 mph Have shudder, let up or increase gas lightly, shudder goes away. had Dealer look at it four times. They can't find the problem. I heard it might be a PCS (pressure control solenoid). Or PCM (powertrain control module) Feels like car is skipping or missfiring ,but checked all electrical and plugs wire, etc...
Any Ideas out there?


Try changing the spark plugs. We had this same problem on our 1999 Buick Regal. It started when the car was fairly new and then kept getting worse over the years. The local dealership and our local mechanic couldn't figure it out. At 80,000 miles I decided to try something myself and changed out the spark plugs. The plugs were supposed to be gapped at .060". One plug was gapped at .068". It looked awful. It came from the factory this way. I haven't had the problem since.

Actually the problem was a combination of a dirty fuel filter and worn ignition wires. Thanks for the reply.

Had a similiar problem at 60+ K miles on the car after changing the spark plugs. The wires were replaced and the problem went away. (The 100,000 mile between tune ups is bunk advertisement from GM) Tune up related for my car, not transmission like I feared.

Had a similiar problem at 60+ K miles on the car after changing the spark plugs. The wires were replaced and the problem went away. (The 100,000 mile between tune ups is bunk advertisement from GM) Tune up related for my car, not transmission like I feared.

I agree GM's 100,000 mile mark for tune ups and transmission service is a real joke. They should put their money where their mouth is and backup the claim with a 100,000 mile bumper to bumper warranty to include emissions and transmission. No wonder people are switching over to rice-burners.

Our '99 Regal LS was great up to 90K miles and then just started to fall apart thereafter, even with good maintenance.

Did Vip64 get this fixed?? I am having the same problem.. when it goes into overdrive it shutters/shakes feels like a real loss of power.

Only mine throws code 77 - EGR solenoid #3 failure. I replaced the EGR valve with a new GM one but didn't help at all. I also notice the shuttering when under light load.... like if you are just lifting up on the brake pedal from a stop - engine runs rough.

So, replaced ignition wires and plugs, still no help and engine code keeps coming back.

wtf?

Believe it or not the problem is a pluged fuel filter. $9 at Wal Mart.

Our '99 Regal LS was great up to 90K miles and then just started to fall apart thereafter, even with good maintenance.

I would have to know what good maintenance means to you. I have had tons of people who tell me the same thing. SO I ask them what they have done. There answer is oil changes every 5 months.

Tire rotations
oil changes
spark plugs
spark plug wires
induction service
fuel injector service
transmission service
serp belts
air filters
coolant service

This list is a long one and I only touched on the major service work considered good maintenance. If you want a full list of maintenance let me know I can printed out GM's recommended service list which doesn't include service needed for different areas of the country.

Quote:
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Originally Posted by bnaylor3400

Our '99 Regal LS was great up to 90K miles and then just started to fall apart thereafter, even with good maintenance.
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I would have to know what good maintenance means to you. I have had tons of people who tell me the same thing. SO I ask them what they have done. There answer is oil changes every 5 months.

Tire rotations
oil changes
spark plugs
spark plug wires
induction service
fuel injector service
transmission service
serp belts
air filters
coolant service


I'd have to qualify that statement and put it into context. Overall, the Regal LS has been an excellent car. It now has 98K miles. I was probably trying to drive a point home in reference to GM improving overall reliability and supporting it with an acceptable warranty.

I hope what I had done qualifies as good maintenance. I had everything you mentioned completed and then some:

tire rotation 5K and oil changes every 3K miles
fuel injector service 50K
spark plugs and wires were changed at 40K and 80K
cooling system was flushed and refilled with Dex-Cool at 50K
ATF and Filter at 45K and 90K
serpentine belt was changed at 40K and 80K (Goodyear Gatorback)
air filter every 2 months
throttle body and screen cleaned at 40K and 80K
all 4 struts replaced at 60K
maf sensor replaced at 90K
CAT convertor at 90K
02 sensors at 90K
valve cover gaskets at 90K

As far as the Series II 3800 engine, its built like a battleship to include the body and structure, however, I seriously doubt the tranny (4T65E) will hold together like the rest of the car. Been through a TCC-PWM solenoid and PCS solenoid just like the others.

I recall my '79 Chevy Z28 with Turbo-Hydramatic 350 tranny made it to over 100K miles with less overall expense and problems. Those were the days in which GM quality was alleged to have been inferior compared to today.