I have a 88 Cherokee 4.0 5spd 4*4. 60K original miles. Almost everytime I start the truck it rev's at about 3k RPM for a few seconds then it comes back down to normal idle. Like it is getting alot of fuel just in the beginning. HELP !!! I did a complete tuneup wires, plugs, dist cap and rotor, fuel filter, air filter and idle air control valve. Do you think it could be the TPS?

Have an 89 that did the same thing, then it became a mystery when it would suddenly rev to 3k r.p.m. Caught me by surprise once- changed out the tps and never had the problem again.

TPS is common diagnosis. It also could be in the cold-start section. I had a similiar problem with a 2000 Grand. Having the t-body cleaned and de-carboned helped. Even though it was a 2000, it had 140K miles!

Made a huge difference, since it almost completely went away with the cleaning, I never bothered changing the tps.

Thank you both for responding. I did clean out the throttle body and that did not do the trick. I will pick up a TPS from Autozone this weekend. I think it cost about $50 or $60. Thanks once again for the response. I'll let you know how it works out.

TPS fixed mine, but that was about 6 months ago.
The only issue now, is it's doing it again. I had replaced the TPS with one from Checker.....This time I just might run to the dealer. SH1T parts.

Thanks tanno for your reply. That stinks that you dont have a warranty for that sensor.

I probably do, but can't find the receipt. And it's been about a year anyway so, warranty is probably shot anyway.

Did the TPS fix yours?

Money has been kind of tight but I plan to work on it soon. AutoZone wants 85 bucks for the TPS.

Btw, Autozone will test your TPS for you so that you would know for sure before replacing it.

DB

Yup....and also, check with Checker....If their price is higher....tell them what Autozone has it for and they'll beat it by 5%.

Best deal in town here! :D

Got mine at a junkyard- could'nt find a store that stocked it- and really was'nt sure if that was the cause of my problems, I have no doubt the tps will do the trick

Could have a vacum leak or a Intake leak.Usally a bad TPS will throw a code. Also check the fuel pressure.

Mine threw no codes, but when mine wouldn't always come back down! It would stay at ~3k rpm!

I also remember someone stating about modifying the TPS or the IAC to stop all startups from going above idle. Because normally, it jumps to about 1200 or so for a few seconds and then back to idle.
He mentioned something about installing a very small washer onto something.....I'll try to find the article again...

I have a 88 XJ,I had the same problem with the rpm running high with starting. I pulled the vacuum off the map sensor and it idled down. The map sensor guages the vacuum on the intake manifold to regulate the how much air/fuel it recieves. And in all I spent $32 dollars at Autozone for a map sensor.

DickBoren, do I just hand it to them @ autozone and they have a machine that will test it for me or do I leave it in and they check it from the vehicle. I thought they only scan 96 and above cars?

DickBoren, do I just hand it to them @ autozone and they have a machine that will test it for me or do I leave it in and they check it from the vehicle. I thought they only scan 96 and above cars?


They helped me with a 87 Camry, but I'd give them a call and find out what they can do and if you can just bring the car down. That has to be better so that they can test several sensors (ie. TPS, MAP CPS, etc). DB

If they could do that it would be great. Thanks for your help.

DickBoren, do I just hand it to them @ autozone and they have a machine that will test it for me or do I leave it in and they check it from the vehicle. I thought they only scan 96 and above cars?



88jeepster, I work at Autozone, they do test most m.a.p sensors and in order to be tested it has to be off the vehical. If you can't make it somewhere like autozone to test the m.a.p sensor take off the vacuum hose to see if the engines idles down. If the engine idle's down it will more likley be the sensor going bad or is bad.

1more88xj, I dont know where or what the m.a.p sensor is. Could you tell me what and where it is? Also, you said that they could check my TPS? Thanks for your help.

MAP sensor is attached to the firewall above the fuel rail.

And yes, the TPS, MAP, CamPS, CrankPS, Ignition Module, and the PCM itself....all can be tested for function. Not only at Autozone, but also at Checker, Parts America, Bemore Carquest, Napa, and don't forget you neighborhood Dealer.

Most of the sensors have to be removed to test. And all have to be unplugged to test. All sensors can be tested by following your Haynes or Chilton manuals.

Why is this topic partial to Autozone?

As far as what a M(anifold).A(bsolute).P(ressure) sensor is, look it up on your favorite search engine, or search this forum.

If they could do that it would be great. Thanks for your help.


if you email me i'll send you a sheet on the sensors that are used on your jeep can't send thru forum dale jeepman600@ao.com

I know it's off topic, but I just couldn't resist....

There is more money being spent on breast implants and Viagra than on Alzheimer's research. This means that by 2030, there should be a large elderly population with perky boobs and huge erections and absolutely no recollection of what to do with them.

Well I finally got the money up and purchased the T.P.S. and it cleared both the high rpm's upon startup and the sluggsh acceleration. Thanks for all your help. I'm a happy camper, for now. Until then keep on with the support! :naughty: :lol2: