Idle Problem
 

Got a little problem. When the car is started, it revs normal for a few seconds then slowly starts reving high, right up to 3K. Then back down again to the normal state and back up to 3K again. It will do it a couple of times, maybe 3 times, but when you tap the gas it drops back down (while it's reving up to 3).

After driving, it won't do it anymore.

My guess is the thermostat is messed, or a PCV valve, or the idle censor. Or I may be way off. BTW, there's no engine light on.

Anyone have any sguggestions before any actions take place.

Thanks :)

Clean the carbon out of the throttle body, chances are there is a little bit of buildup and the throttle plate is not closing all the way, just remove the intake hose off the t body and wipe it out with a rag, that is probably why when you hit the gas pedal it closes completly, either that or the iac has dirt in it. if it was a sensor or mechanical failure, first of all the light would come on and secondly it would do it all the time

FICV - Fast Idle Control Valve problem or carbon buildup... also, do you have the right amount of slack in the throttle cable?

my idle was surging like that... i took apart the iac valve, it was ceased.. cleaned it out, and idle is back to steady

I had a similar problem, and cleaning the carbon fixed it for me.

Thanks a lot guys, im going to give it a test soon.

End result: TPS sensor

thx guys

damn, that was quick :) so any explanation as to why it smoothed out after it warmed up?

Just wodnering what is TPS Sensor? What does T.P.S. stand for?
I have the same problem with my car and my engine light is on occasionally too.

from what i understand , TPS stands for throttle position sensor... what does it do? *shrug*

Jay

measures throttle plate angle.

The TPS is basicly telling the ECU how far you have the gas pedal pushed. It puts out a voltage depending on how far the throttle is opened/closed.

it doesn't "put out voltage" as you put it... it takes a reference signal of 5V from the ECU, and that 5V goes through a variable resistor, where resistance decreases as the throttle plate angle increases. Then, there is a wire back to the ECU, with the adjusted voltage. So at closed, the ECU gets back ~0V, and at wide open throttle the ECU gets back most of its original reference signal (~5V).