A rough idle and even an emissions inspection failure for high HC and CO can be caused by improperly adjusted valves. Also, exhaust valves may become to tight which can lead to valve failures. Our technicians tell us that regular valve adjustment inspections are a must.
Improperly Adjusted Valves May Cause Emissions Failure/Rough Idle on Toyota RAV4
Average mileage: 314,000 (314,000–314,000)
3 people reported this problem
Rough idle, and by jumping. Codes for 4th cylinder missing, and blocked catylitic converter. Upgraded intake, cleaned erg valve, cleaned throttle body, full tune up, removed cat: Replaced with straight pipe. Removed muffler replaced with heartthrob turbo muffler. Replaced worn pads and shoes. Next will have valve job done