werid idle, almost stalling

[InjenTalon96]

hey guys i have a weird idle problem, sometimes at full operating temp, my car will idle normal, about 800-900 rpm, then sometimes it will idle at or around 1200-1700 rpm, or sometimes it will get really low, 600-700rpm, which causes my car to shake alot, i was wondering if that it a sensor that i could replace

 

[boostedinaz]

There are a few things that you should do to fix this.

The first, and most important thing, is to do a leak test on your intake tract. Make sure there are no leaks in any part of the system. Most common leaks are in the hose couplings and TB. I got those fixed on my own car, but my injectors seasl are leaking so my idle does the exact same thing your does.

If that works out well, then try and swap out the IAC motor with one that you know works. The job of the IAC is Idle Air Control so it will have a big part in idle quality. You may have a hard time trying to find a 90 IAC and I am not exactly sure is a 91-99 will fit on a 90 TB.