My 01 automatic v6 stang idles at about 2-2.5 and does not come down unless I put it into gear. It never did this, and now it happens on and off. Any reason?
If i had to guess without looking at the car i would guess the Idle Air Control Valve. its actually becoming a big problem with the mustangs, and with mine it will speed up when i let out of the gas or step on the break, but it would still be the same problem probably. you can get them at autozone but i can't remember how much.
When was the last time the PVC value was replaced? Really? That long ago? Well it's time to replace it.
Now get under the hood and do a through look for vacuum leaks. Then read the following post on how to trouble shoot IAC/Idle issues. Post back with the test results.
A little reminder, when the car has trouble idling, and settles down when its put into gear, kinda sounds like the IDLE AIR control valve is bad, just saying its the most obvious