My 90 gs has 163xxx miles on it, I just got it saturday. Yesterday I noticed the idle revs up and down about 500 rpm sometimes, then it'll just sit at 1500 for a while. Then the revs drop back down to like 700 or so. It normaly revs about 700. What causes the idle to do that? Should I be worried about that?

 

take the fast idle air control valve out and clean it (IACV). I just had mine done yesterday..solved my erratic idle on the spot. Mine went from 1-3k .

 

I haven't done to much mechanical work...where would I find the IAVC? And would it be hard for me to do?

 

Viola!