What Causes the Chevrolet Cruze's Idle Speed to Fluctuate?

[KyleRose]

The Chevrolet Cruze's idle speed fluctuation may be caused by the following reasons: 1. Excessive carbon buildup in the throttle body: Air intake manifold or various valve leaks. This malfunction directly affects the quality of the fuel-air mixture and combustion efficiency. Possible leak points include the intake manifold, vacuum tubes, charcoal canister purge valve, exhaust gas recirculation (EGR) valve, positive crankcase ventilation (PCV) valve, etc., which require individual inspection and repair. 2. Valve timing malfunction: Incorrect valve timing, improperly installed timing belt, excessive carbon buildup on intake/exhaust valves, broken valve springs, etc. Uneven air intake across cylinders leads to unstable idle. 3. Clogged catalytic converter: A blocked catalytic converter not only causes idle fluctuation but also results in insufficient power. 4. Fuel injector malfunction: Issues such as poor fuel atomization or clogged injectors require injector cleaning. 5. Low fuel pressure: Mainly check for blockages in components like the fuel filter and fuel pump, or whether fuel lines are deformed, among other potential faults.