Ok here's the deal. I bought a car that has been sitting for a while. I got it all put back together and now I am having a problem with the idle.

1. When I start the car cold, it revs high at around 2000rpm.
2. After the car gets to temp the idle jumps from 1000-2000rpm.

I was thinking that it could be a EGR valve or a vacum leak but I was thrown off when I turned on the AC.

3. When the AC is on, it idles steady and fine at 1000rpm.

I have already reset the ECU and nothing helped there.

Sorry if this is a dumb question. Any info is much appreciated.

 

I had the same problem with my idle, I found that I had a pin hole lead in the lower pcv hose, replaced it and idles perfect.

 

Check for vacuum leaks, and check the IAC valve.

 

Did you ever solve this problem? You described the EXACT symptoms I'm having with a 91 honda accord lx wagon. I sure would love to get it fixed. I don't have a manual.. so describing locations of things would help me a ton.

 

Check the idle air control valve, and for vacuum leaks. The IACV is under the intake manifold, vacuum hoses are self explanatory.

 

also check the fast idle thermo valve, if equipped.

 

i'd check for vacum leaks first...if not check for iacv, and if not this check and make sure all sensors are connected

 

why is it such a problem if your car iddles badly?

 

^ is that a serious question?