I let the car get good and hot, cooling fan cycled a few times, and topped up coolant. Any ideas??

 

 

did NOT replace TB gasket (was not expecting to remove it today) will replace on monday I hope. Will also check timing (unrelated but needs to be done), hope to report back with good news.

 

Does covering the IACV port in the throttle body with your finger stop the idle speed fluctuation? If not, the IACV is not the culprit.

Are you saying that you think that the TB gasket is leaking?

One way used to test for intake air/vacuum leaks is to spray carburetor cleaner around suspect leak areas while the engine is idling. Any change in idle speed suggests the location of a leak.

By the way, have you yet verified that the idle screw is adjusted as specified in the service manual?

 

Idle screw was not touched, and previous to TB/IACV removal warmed-up idle was approx 600. I suspect TB base gasket, and possibly PVC system leaks. Will check with carb cleaner and report (nothing is open in this stupid town on sundays[:@])

 

I reset the idle screw (musta bumped it) but still getting wierd fluctuations. does not appear to be vacuum leak. maybe TPS sensor?

 

The idle fluctuations seem to happen more mid-day, esp if outside temps/humidity are getting high. 25C/77F with higher humidity(about 60%) seems to be a common theme when it acts up. It doesn't act up when the engine is cool, or in the evenings...

 

I also drained about 1/2 can of carb cleaner checking for vacuum leaks, nothing changed.

 

Does covering the IACV port in the throttle body with your finger or disconnecting the IACV connector eliminate the idle speed fluctuation?

 

I will try that next time it acts up (provided I'm not in traffic or something) any way to check the resistance of it? what are the specs?