Problem with Accord Idle...

[Slaccord]

Someone, anyone Help. K I have a 91 accord, the problem is whenever I Start the car and let it warm up, the Idle jumps from roughly 900 RPM to 2500 RPM... I checked the (IACV) Idle air control Valve. Also check the Fast Idle Thermal valve, and the EGR.. None of those solved my problem. A friend of mine says it could possibly be an Intake Manifold leak. (bad gasket) Well if anyone can help me that would be great.
Thanks

[jeffcoslacker]

Does it surge up and down, and does it drop after it warms up eventually?

[Slaccord]

Yea... it surges. Even after it is at normal running temperature, it still does it.. When in D4 it tries to pull slightly through gears. not even on the gas...

[Igovert500]

Are you getting any Check Engine lights or flashing D4 or 'S' lights?

To have teh idle fluctuate that much, it would have to be a pretty significant vacuum leak. So I'd check the intake manifold as you mentioned and all the vacuum hoses, etc. I would think if it's that big of a leak, it should be rather audible/apparent.

Bad o2 sensors would probably throw a CEL.

[jeffcoslacker]

A real easy way to hunt vacuum leaks is to spray something all around suspected areas, pretty much anything works, even water, but heavier stuff will "creep" and find leaks in the underside of manifold runners etc, where you can't see. I've used carb cleaner, WD-40, water, starting fluid.

Depending on what you use, the engine will react if it inhales the spray through a leak, either by picking up speed, bogging down, or idling at correct speed for a few seconds.

I don't know if your motor was one of them, but I also remember some Asian motors were known for rolling idle when the coolant was really low also...it'd surge across the sensor, giving varying readings of temp and the PCM would react accordingly, by trying to raise the idle and richen the mixture.

[Slaccord]

Well Im not getting any codes. I have yet to check out under the Intake Manifold... But I will definately try the carb cleaner spray to test it. But I also heard today that it could be dirty fuel injectors?!? Im going to try Injector cleaner, see if it helps.

[EZFrank]

My 91 was doing that and it was the pcv valve on top of the valve cover check that cause i went through all the vacuums and couldnt find the problem till i pulled the hose at the pcv. Good luck

[Slaccord]

well guys I broke down n gave up on it, because I had no idea.. The shop tells me its the intake manifold gasket...I replaced it , and it was back to normal again... thanks for all the help.

[superdesi]

It took me 2 months to finally figure out what was causing my surging idle. During that troubleshoot, I cleaned the IACV, replaced the FITV, cleaned the EGR with a new gasket, cleaned the TB, etc, etc.

I finally discovered a huge air leak where the intake manifold meets the head.
I am going to try to tighten those bolts to see if that helps.

Does anyone know of an easy way to replace the intake manifold gasket without actually removing the entire manifold on the F22A1 engine (92 Accord)? Any short cuts?

Thanks.