idle sticks at 1500 rpms even after warm up

[etniesfaction]

i have a 97 eclipse gsx and for the last month or two its been idling at 1500 rpms and when it first started i did have a check engine light for an iac sensor and i replaced that and didnt work. i no longer have a check engine light but the idle is still up at 1500 rpms even after warm up. what does this problem sound like?

 

[grnchevyz]

Was the replaced IAC new or a known good one? If not, it may be faulty as well. The other thing you can try is reset the ecu and let it re-learn.

 

[stevo911]

When you put the IAC in did you change the gasket?

 

[etniesfaction]

yes i put a new gasket in when i replaced it and it was an iac from napa but could the iac go bac and not have a check engine light come on and could it also be a fiav or something?

 

[stevo911]

IAC can go bad without a check engine light but you said this is newer? Try a multimeter test? FIAV can go bad and they are known to go bad so its possible. Also did you readjust your biss screw? Chances are trying to fix the idle you knocked it off which would account for this. VFAQ Site - Visual Frequently Answered Questions under intake youll find the directions to set it.

 

[etniesfaction]

oh ok ill give the biss screw a shot but my other question was sometimes at a light my idles will be a 1500 and bump down to 1000 quickly then back up to 1500 but this happens once in a blue moon.

 

[stevo911]

Mine does it all the time when I hit red jumps 3-4 times then steadies. Was told it was the CAS but never bothered replacing it just a small inconvenience.

 

[etniesfaction]

it just gets irritating thats all little stuff like this bothers me so i mean what else am i left with to do also i did check the iac resistance and they were all greater than 30

 

[stevo911]

Should be good honestly sounds like a leak in TB. I would remove make sure all gaskets are secure and not broke and remount. Also remount the IAC just to make sure it was seated correctly.

 

[aaronhawk60]

Sounds like you may have to set the BISS I had some idle problems and I checked my IAC and I ended up setting the BISS and the problem went away

 

[BoostFrenzy]

First, reset your ECU if you didn't do so when you swapped out the IAC. The positioning could be all kinds of off. Let it relearn and see if it changes anything.

Then if it still persists, do a boost leak test to see if there are any leaks by or around the throttle body elbow/throttlebody/intake manifold. Also, swap out any old VAC lines that may be leaking as well. Just do them one at a time so you know where they all go.

Another thing that may be causing a leak would be your fuel injectors. Half of the time, a bad seal on one won't do anything at idle but will be seen under boost. If it is a real bad one, then it will show it's ugly head around idle. Should be able to see if one's bad with the boost leak test.

If it still persists and you made damn sure there are no leaks anywhere, then go ahead and adjust the BISS with the proper procedure described on the VFAQ.

While you are at it, you might want to also get the ECU rescanned for codes just to make sure.

 

[etniesfaction]

could it be a leaky intercooler because i got a supra sidemount that looks pretty beat up?

 

[stevo911]

Boost/Vacuum test

 

[RedTurboEclipse]

no one suggested checking if the throttle cable is too tight.

I had issues like this before, when cold its fine and i accurately can tell by the TPS showing 0%. As the car warms up, then it seems to stick at 1%. a quick tap of the throttle will "loosen" things up a bit and get it back to normal.

So check that if all else fails.

 

[etniesfaction]

my throttle cable is pretty loose i mean its no where near too tight at all