Idle Help


My car this morning started doing this rev up and drop thing after I drove it to work . I noticed it when I parked it at work and was getting ready to shut it off and I watched it rev up a little and drop off and do it over and over.

Any ideas :shrug:

Let me know ASAP


1st check your coolent level then check for vaccume leaks.

The idle climbs up because of excess air which the map sensor sees and then the ecu responds by enriching the mixture ie… more gas and the idle climbes until it passes around 2500 then it shuts down to min idel around 550 and the process repeats.

The reason it hunts between 2550 and 500 has to do with the idle logic of the ecu with the throttle shut.

Your IAC opens up the idle bypass port when it is cold hence why to check your coolent level.


Just had the same prob. HTH


Same prob with idle

its not a vacuum leak or would starting fluid cause it to rev?
coolant is ok

what now???:bang:

could be o2 sensor

Originally posted by Zyban
could be o2 sensor

O2 snssor has nothing to do with idle, all it does is help the ECU determine proper air/fuel except at WOT.


not o2

it not the o2 sensor its only 3months old:bang:

it’s your IACV or your IATV just requires a lil cleaningmos tliekly it is your IATV, it is located right under your thorttle body. it has 2 coolants running into it and 2 bolts holding it in place. get some intake cleaner and spray into it. and then let it sit and dry for 30 minutes and she shoudl be running good.