Additional Symptoms Tests: Notes
WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Detonation/Spark Knock
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Test the engine for an overheating condition. Refer to Symptoms - Engine Cooling .
- Poor Fuel Economy
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Inspect for foreign material accumulation in the throttle bore, and for carbon deposits on the throttle plate and shaft. Also inspect for throttle body tampering.
- Rough, Unstable, or Incorrect Idle and Stalling
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Inspect the engine mounts.
- Surges/Chuggles
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Test the heated oxygen sensors (HO2S). The HO2S should respond quickly to a change in throttle position. If the HO2S do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The ECM reduces the amount of fuel delivered to the engine, causing a driveability condition.