I recently started having this prob with my boosted H22. High idle after driving for about 10 minutes. It will give the normal high idle (1500) at cold start then will fall to about 800 after it is warmed ( in about 5 minutes). But if i take it for a spin, by the time i get back it will begin to surge 1000 -1300-1000 for a few minutes then it will rest at about 1100 , which is to high. I alreay checked the fast idle valve and replaced the iac valve, but it still happens. I also have no vacum leaks.

Any suggestions??

 

Check your throttle cable for adjustment? Might be stickin? But could be somethin else.

 

well if you did those things the next thing to do is bleed ur coolent...or make sure there is no air in ur radiator..that can cause it to ide ruff...