My car was surging when warming up and last time I fixed this by changing the IAC. I realized that when I took off the old IAC that it was dirty. It passed the tests so I think that probably that was the problem. So to clean the current valve I soaked it in some isopropyl. I left it in the sun a while to dry and then I put everything back together. The car would not start at first and then after cranking and giving a little gas it started. The CEL came on and stayed on regardless of reset battery. Engine is runnig a little rough and not sure what it does cold because it hasn't cooled down enough to see what the cold idle is.
Do you think alcohol was still in the controller part of the IAC and burned it out? Or maybe it just needs more time to evaporate?
Can't really think of what else it could be.