Chevy Monte carlo, 98 3.8L v6December 6, 2013What is the normal RPM for a 1998 chevy monte carlo, 3.8l v6? Keywords:monte carloRPM 1 thought on “Chevy Monte carlo, 98 3.8L v6” Freeautomechanic December 6, 2013 at 10:23 am Normal idle on cold start up is around 1500 rpm. While the engine is warming it will start to come down on its own. At Normal operating temperature the engine will idle around 1000 rpm in park. Once put in gear, between 750 and 900 is normal. If it is idling lower, take a rag and spray it with carburetor cleaner and wipe the inside walls of the throttle body and butterfly. DO NOT spray carburetor cleaner into the throttle body as it can be harmful. If you have a really high idle, check for a vacuum leak. Comments are closed.