98 GTP high idle problem

[mikegtp]

I just bought this car yesterday. I was driving it today and found that on a couple of occasions the idle would be very high. 3000rpm in park. I pulled the code and it indicates the idle control system high idle (code 507). Where do I begin??

Would it be the IAC? If so, do I clean it or replace it?

It also seems to shudder a bit under hard acceleration.

I am new to this forum. Any help would be great.

 

[Liquifire]

I don't know if this helps or not, but I would check for any vacuum leaks, but that is just a guess. I don't know what that code is specifically, but good luck.....I am sure someone more knowledgeable in this area will chime in.

 

[blueguy]

Yup...sounds like a toasted IAC...you can try cleaning it but I would just get a new one...also check the black rubber "T" fittings around the LIM and under the blower snout...they tend to rot out and cause crazy things to happen

 

[mikegtp]

I cleaned my IAC tonight. Need to do the test run tomorrow. It only happens sometimes when the car is warmed up. My IAC didn't have an o-ring. Should it? If its supposed to have one then I am guessing that when its warmed up a vacuum leak occurs around the IAC, hence the fast idle.

 

[wifegrandprix]

I cleaned my IAC tonight. Need to do the test run tomorrow. It only happens sometimes when the car is warmed up. My IAC didn't have an o-ring. Should it? If its supposed to have one then I am guessing that when its warmed up a vacuum leak occurs around the IAC, hence the fast idle.

Did you every fix the problem? Have anyone else had this problem and how did you fix it.

 

[mikegtp]

It ended up being a vacuum leak on the intake manifold vacuum line tee. The one under the supercharger pully. I fixed it and the problem went away.

I fixed another problem too where the car would start up, then stall right away. It was a bad IAC.
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