Almost every time I go to start my car either cold or it sitting for a few hours after being warmed up it revs up to like 2500-3000 for one second and then goes down to normal idle. I'm guessing this is not good since there's not as much oil pressure right when starting and would cause additional wear.
I've tried to tighten the idle screw a bit but doesn't seem to help too much and then it dies when warmed up at idle if I don't give it gas.
So could this be the iacv since when I tried to clean it, the screen was still a bit dark for some reason after spraying it multiple times with brake cleaner. Or could it maybe be air in the cooling system since I had to remove then coolant hoses for the iacv.