2000 accord worsen rough idle

[Voltmaster]

Hi,
My 2000 accord SE (2.3L )has had rough idles for a while and I've noticed its gotten worst.

The idle drops to about 250 Rpm , feels like its gonna stall then ramps up to 750 rmp after about 2 seconds.

I feel like its worst when car is cold and also when AC is not on. Not sure if its related or not, its my observation.

Not sure what to look for here, no oil presure light, and CEL has been on for months p1486 which is thermostate reading error. Prob. just air bubbles and/or thermostate is going back, its a common problem that does no harm.

no over heating or anything.


plug was changed about 10k ago with NKG irridium XI.
Wire set is NKG also.

Transmission failed abit ago , rebuild with external cooler.

everything else is what it was shipped from factory.

 

[cknight49090]

I would check on the honda forums for your code could be a failing temp sensor.Try cleaning the IAC and check for a vacuum leak.

 

[fdcg27]

Check the boot from the AFM or whatever it actually is on this car to the intake manifold.
I supect that you may have a vacuum leak downstream and the engine is trying to run leaner than it should, and it surges as the O2 sensor enriches the mixture to correct the excess of O2 in the exhaust stream.
There would be no problems in normal running if this were the case.

 

[user52165]

"CEL has been on for months"

Amazing what fixing a CEL condition will do. These systems are inter related.

And you won't pass a CA smog test with a CEL.

 

[artificialist]

Originally Posted By: fdcg27
Check the boot from the AFM or whatever it actually is on this car to the intake manifold.
I supect that you may have a vacuum leak downstream and the engine is trying to run leaner than it should, and it surges as the O2 sensor enriches the mixture to correct the excess of O2 in the exhaust stream.
There would be no problems in normal running if this were the case.

The Honda would probably use a MAP sensor instead of a MAF, but a vacuum leak can cause a variety of problems. Sometimes when a vacuum leak occurs on an engine with a MAP sensor, RPM goes up even with the throttle fully closed. I could see this causing trouble with the idle air valve system.

A stuck PCV valve or worn PCV spring could do this. I suggest getting an OEM PCV valve, even if your current one still clicks.