I have had increased idle speed fluctuations as of late with the idle going from 1000rpm to near stall mostly when the car was warm but sometimes even cold. It would drop down to near stall and then come back up to 1000rpm three or four times in 15 seconds and then stabilize on its own. Then 3-4 minutes later do this again. Read a post about removing and cleaning the ISV with brake cleaner and am happy to report this seems to have "nearly" stopped the idle hunt. Next I will clean the MAF with CRC air intake cleaner as suggested in an associated post and if that does'nt fully stop it I think that a new head cylinder temp sensor will be next. Looked for vacuum leaks but could'nt find any thing shockingly obvious. Any other suggestions welcome.

 

Ck to make sure the idle switch is working. Ck it with an ohm meter not just to here it "click".

 

I had the same problem. I replaced the ISV, head temp sensor, and O2 sensor, but nothing helped. Then, someone suggested having the mixture adjusted. I took the car to my mechanic, and he tweaked the mixture. Haven't had the problem since. Sometimes the simplest solutions are the best.

Scott

 

Disconnect the O2 and the ISV plug, and spray starter fluid anywhere a vacuum leak could be suspected. If the idle shoots up, you have a leak.

 

Thanks to all for the additional tips and ideas. I drove yesterday to Lahaina for dinner and what a torture trip. A new traffic signal that is not set properly had traffic at a standstill/ bumper to bumper, idled my car for over an hour but the temp stayed at the 9 o'clock position for the entire time. Holidays and extra tourists = very slow driving. The good news is that there is no hunting at all now!! The trip home after dinner was a pleasure, 10:30 at night full moon in front of us and now zero traffic. Ah the pleasures of a empty road and a well tuned 3.2