So took my 96 out today, and while sitting at a stop sign the engine would surge up and down. Would idle at 1k, then drop to 500 and then go back up. Vacuum line maybe? its also doing this while go just driving around too. any ideas?

 

Could be a dirty throttle body causing the IAC to stick a bit while it is attempting to control the idle speed.

 

but what would be causing it to surge while driving?

 

Did you make sure your intake is all connected? I was having weird surging issues when my intake hose was loose behind the MAF.

 

Good call! Yeah, if the valve cover vent line to the back of the intake hat is off, it can definitely cause surging..

 

thanks all, will check it out this weekend with 86Blazer4x4 when we get some time.

 

Good ol EGR-valve sticking?
PCM fried(I strongly doubt it,but it was my year long issue with my '95 the mechanics could not even find,until i voiced such)