Posts Tagged: fluctuating idle

Rough idle, high idle

March 27, 2008

Rough idle, high idle Both a rough idle, high idle can be caused by a vacuum leak or carbon buildup in the throttle body. Diagnose and fix a car has rough idle condition Any time you see a rough idle or hunting idle (idle speeds up and slows down), suspect a vacuum leak. Extra air leans out the exhaust mixture, which is detected by the oxygen sensor and reported to the powertrain control module (PCM). To correct the lean condition, the PCM adds fuel. As the engine speeds up, the … Read More