My 91 DA normally idles at 1500, yeah i know its high.
But sometimes when stopped it will drop down to 1000 and go back to 1500 and it keeps going up and down and its hella annoying.
Ive already took off the IACV and cleaned it.
Any idea what the problems is?

 

theres also an allen style screw on the iacv that you can adjust. play with that and the screw on the throttle body. Also check your powerbooster to see if theres a leak. There some kind of gauge that you can connect to it in place of the holes that go to it.