my car when it semi warms up has a nasty idle problem. it varies from 1000-2300 rpms ina cycle. also when i step on the gas, the car hesitates. sounds like its running on 2 cylinders..
btw it my 91 gs auto

 

maybe a dirty air filter

 

Dirty or clogged IACV. to test it,

locate the IACV (on top and behind the intake mani with 2 coolant lines and 2p harness)

warm car up to reg temp

pull the harness off while car is running, and if the engine does not stall or fluctuate in rpm, your IACV is clogged or dead.

First pull the valve off, spray the screen and the other hole with carb cleaner. Drench it.

Then put it back on and test idle.

Or check for vacume leaks

 

hrm, cool. ill try it today