when i cold start my car is goes up to 4,000 rpms and goes down then back up to 3,000 and down, hitting the gas makes it surge again, i replaced the IAC valve put gasket sealer on the valve covers. I dont know whats wrong with it somtimes it doesnt do it.

 

What year and engine? Sounds to me like you have a vacuum leak

 

95 3.4 dohc I sprayed all hoses with either no change so it's not a vacuum leak

 

maybe this will help i had a radiator leak and i replaced it with a used one and did not bleed it, or follow the special procedure needed would that cause the surge ?

 

have you done a tune up recently it may help cut it down. also does it have a maf sensor it also can do it as well. but go after some thing simple first like check all of the wires for the spark plugs as well as change the plugs. if it didnt change it also may be the computer going into defalt stage glitching making it have a iratic idel

 

i forgot to mention the temp sensor also could do that as well it will make the temp gage read normal but when it messes up it will read normal but runmessed up till warm.

 

also the thermostat as well when it is stuck open