Ok, for about a year or more now ive been getting this intermittent high idle problem. It happens the most when its hot out and im running the AC. It hasnt been acting up but for the past week oregon got a big heat wave (106 out in Portland, Rare!) and almost everyday after about 10 minutes of driving my idle sticks between 1500 and 2000 RPMS. Its not an up and down rapid thing, it sticks. Ive already replaced the sensor that everyone talks about idle problems(IACV) Does this sound like a vacuum leak or some kind of sensor fail? How does 1 check for vacuum leaks?

 

Nobody has any ideas?

 

If you turn the ac off while the idle is high, what happens?

 

Stays the same. Stays high. It hasnt been idling high today, and its usually fine late at night when its cooler out.

 

sorry to bring this tread back but the exact thing has started happening to me with the ac on but only when its really hot out. any idea what is causing this?

 

When the AC comes on the IACV is supposed to open. It must be opening too much then slamming shut, opening again, and so on. Im pretty sure a new IACV is in order.

 

Have you found what was the problem ? I'm having the same problem on my TL. It did once b4 my I/H/E install but has been happening more after the install, specially on hot humide days. I've been told it could be TPS sensor or even a dirty TB and butterfly. Gotta check it out.

 

sounds like IAC (some what common in these vehicles) take out and clean... many threads about this problem and easy DIY