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1998 GTP will not idle cold and revs to 1500rpm by itself when warm.

F

flyerboy101

New member
1998 GTP. Got car and put 10,000 trouble free miles on it.Oil changes and fuel filter etc.Would not start at work the other day.Fuel pump.Car has 192,000 miles on it, got a new fuel pump assembly installed and car ran fine for 1000 miles.Now a cold start requires some throttle pedal to keep it running till it warms up.Driving it will rev up to 1500 rpm by itself.Been reading the grand prix forum for problems like this.and i see parts being replaced and sometimes the problem is still there.I do have a sevice engine light on.In the last 10,000 miles of driving I did have this light come on before but temporary,as in the next day the light was out but now its on steady,thank you for any input into this problem I have before I replace parts,.
 


If the check engine light is on, I would go to a auto parts store (ie. Advance) and have them scan the car for the codes. Write them down, post them back to us and we can really go from there.

Otherwise, it could be any number of things, vacuum leak, MAF, MAP, etc... BUT if you get the codes, we would know why the light is on, and be able to help you narrow it down alot easier.
 
Thanks for your help and support. Pulled the throttle body and cleaned it with throttle body solvent.Pulled the idle air motor out of throttle body and cleaned it good.Put it all back together.The car fired right up and no sevice engine light.Did a good test drive and all is well. no idle problems or reving up or surging. PS, there was a medium amount of black residue on the engine side of the throttle body and the throttle plate and the mechanism for the idle air motor, the cleaner worked good,Have a great day!
 
flyerboy101 said:
PS, there was a medium amount of black residue on the engine side of the throttle body and the throttle plate and the mechanism for the idle air motor...
Click to expand...

Glad you got it cleaned up and back to working well. Just so you know tho, it will get black again and buildup is *almost* always going to happen. The reason being the EGR system dumps exhaust gases full of carbon back into the intake just after the throttle body. The carbon gets everywhere inside and will build back up as long as the EGR is still hooked up. You will just have to keep an eye on it and clean it again if the problem re-occurs.
It will take a while to build up, usually a couple years, but it will happen again. Just so you know.

Again, glad you got it fixed!!! :th_thumbsup-wink:
 


You have to unbolt the EGR parts, block off the now existing hole in the intake manifold, and the exhaust manifold. Tune so its not throwing the codes for a missing EGR system, and your good.

Why do you want it gone?

If it is just because of the "carbon" deposits, you shouldn't worry, its not like people will be looking for carbon inside the motor lol. It helps clean out the exhaust and I think may provide a little better fuel efficiency. The only reason to really get rid of it, is if you get headers and don't need the EGR and plan to tune it out anyways for future modding... If it will stay stock and a DD, leave it alone and don't be so anal about black stuff inside your motor that you can't see anyways.
 
anal? whats your problem? most people on this site show respect and share information.I could use some chioce words but you are not worth it
 
Bahaha wow. Ok, my appologies. Lets see if I can word this so your feelings don't get hurt?

Why do you want to remove something off your stock motor that will harm your emissions and reduce your MPGs???
 


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