Im having a problem since quite some time bow but cant figure out the problem. Problem is the RPM isnt stable when car reaches half mark temp. The rpm goes down to 500 n then comes back up to 750. Ive cleaned the IAC thoroughly but still no good. Im going to get plugs changed and see if that solves the problem any other idea? There is no missing . car is only driven on petrol. Please keep in mind that this rpm fluctuation only occurs when temp is at optimal level. And this problem dosnt stays for long either. If i keep driving the car around, the rpm would fluctuate on idle only and after some time it gets stable.