Can coolant sensor affect RPM.
when car is hot, RPM drops.
please help what i need to do first to push my RPM to the normala position?

Lower the voltage (cold) the RPM raises, & the ECU adds up to 5% extra fuel & timing a 1/2 step at a time up to 2* advance.
Under 150-158*F of coolant temp, the transmission locks out any over drive gears.

Raise the voltage & RPM drops & the fueling/timing is normal.

I think you've nailed a consistantly bad RPM problem with the CTS. Good self-troubleshooting!



If you check the CTS & it's good, don't underestimate the power of a post air sensor vacuum leak!