ok so my camaro V6 3.4 auto is idleing to 1500 rpm. ive changed the IAC valve like 20 times and "restarting" the computer it would idle fine but after a couple of hours it would idle high again!!!! theres no vacuum leak. this has happen before but i simply changed the IAC and worked fine.

funny thing thou, the new one i put this morning was a new IAC still does the same thing but when on drive and letting go the gas it idles up and down between 500 to 900 rpms until i fully stop.