Posts Tagged: idle goes up and down

Idle Fluctuates Up and Down? Common Causes

7 Most Common Issues That Cause Idle Fluctuation at Idle Quick Summary Engines need a precise balance of fuel and air at idle. If airflow isn’t measured correctly, fuel delivery isn’t stable, or exhaust readings are distorted, the engine computer constantly overcorrects—and that’s when the idle fluctuates up and down. The most common causes include: • Vacuum leaks • A dirty idle air control valve • Carbon-packed throttle body • Failing or dirty MAF sensor • Exhaust leaks • EGR valve malfunctions • Fuel-pressure problems. Fix the air and fuel … Read More