I have an 1999 mitsubishi eclipse gs. When i first startthe car it sounds like its about to stall and after ive started it it runs rough sometimes, with the rpms dropping below normal and going back to normal. Also, when in neutral, the rpms sometimes go higher than normal and stick for a few seconds before slowlyreturning to normal.I took it in to a shop today and they said they couldnt find anything wrong except it wouldnt hurt to change the plugs and wires.I did that but the problem remains. any suggestions?

 

Turn off your AC and see if it still changes RPM's.

 

my guess is a bad sensor or an air leak. Do you have a CEL?