So I have a 98 Accord ex I4, and when it idles the rpms jump from 1000-1500 then back down, then back up and that keeps going on and on and on. Its not just the tach because the engine itself is revving. Any mystical wisdom? I've already taken off my IACV and cleaned it out.

P.S. I'm a new member, so I'll post a video when I can.

 

Had the same problem but for me I had to replace the iacv. Iwas told that air could be trapped in the cooling system that you should try to bleed it out.

 

I've already bled the coolant. How much does an IACV run for? Should I check local scrap yards or do I have to buy new?

 

Igot min from oriellys for $150 but if you know of one being parted out that would probably be better. If you take off your air duct assembley there'll be a small port that leads to the iacv.. If you cover it with a rag and the idle drops down to normal its most likely the iacv but if the idle continues to bounce around its probably a different cause or air leak

 

Have you ruled out low tech, old fashioned vacuum leaks?