High Idle Problem [Archive] - GrandAmGT.com Forum


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03-01-2007, 02:24 PM
hey guys, this is on my moms 2000 grand am SE 3400. Sometimes the car idles at about 1500 rpm, and will not come down. Throttle cable is not sticking and the plate is fully closing. I pulled out the IAC, cleaned out the passages, made sure the motor wasnt stuck, and checked the o-ring. Once I did this the car idled at 3000 rpm, and would not come down. So I disconnected the battery for a few minutes, and then started the car, and the idle was fine, right at 600 rpm or so. Then it was fine all day until my mom drove home from work, and even when in gear the car wont idle, so you have to put it into neutral if you want to stop. Anyone have any ideas? There has been no SES light, and I dont have the equipment to check for any codes, is there a way to check without an OBD2 scanner? I have a spare IAC, and Im gonna try that, but I dont think thats the problem.

el nino
03-01-2007, 02:29 PM
u should go get ur codes checked at an Auto Zone. if they have those in canada...;crap

03-01-2007, 03:56 PM
There has been no SES light,

no codes for ses means no codes for a generic tool to read. a real scan tool could but it sounds like the IAC, because the only other thing that would change the idle is the PCM. also make sure to check the harness as well. if you can get ahold of a real scan tool, it can read current codes that did not set the SES light off.

03-01-2007, 05:37 PM

03-01-2007, 09:04 PM
I second TPS.

Also Gectek there are some codes require consistent failures at startup in order to turn the SES light on. The TPS codes are some of these codes.

03-01-2007, 09:23 PM
i know that is why i said that you can read current codes, which are not hard fault codes, and yah TPS also, forgot about that

03-02-2007, 10:11 AM
Cool, thanks guys, Im going to change both the IAC, and TPS, see what happens.

03-02-2007, 01:51 PM
i know this is going to sound stoopid, but i had the same exact problem with mines....did the same thing but forgot to plug in the iac again.

idle is fine now.

another thing that could cause high idle is a vacuum leak.

03-02-2007, 08:29 PM
well a vacuum leak would make the engine run like pooh though, and it would turn on the SES, and also it would be very noticeable, especially with a higher idle

03-03-2007, 12:52 AM
i had the same problem. it would randomly jump to 1500 and then back down after a few minutes. i had that tps enhancer mod or whatever and got rid of it then it was fine.

03-05-2007, 10:42 AM
I had the same issue as well... turned out to be the TPS.....

03-06-2007, 05:49 PM
Looks like it was the TPS. thanks guys.