Possible Causes & Corrections
WARNING: This page is about a different car, the 2003 GMC Sonoma and 2003 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
Check the following items:
- Search for bulletins.
- Verify that PCM grounds are clean, tight and in the proper locations.
- Remove air filter element and inspect for dirt or for restrictions.
- Inspect for incorrect fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L SONOMA & S10 PICKUP article.
- Inspect for a restricted fuel filter.
- Inspect for a contaminated fuel condition.
- Inspect fuel injectors. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 2.2L SONOMA & S10 PICKUP article.
- Inspect for the following that may cause engine to run rich: Water intrusion in the HO2S connector, engine oil contaminated by fuel, EVAP canister purge condition, incorrect fuel pressure, leaking fuel pressure regulator, leaking fuel injectors, any vacuum hoses that are split, kinked or improperly connected, an air intake duct that is collapsed or restricted, or an air filter that is dirty or restricted.
- Inspect for the following conditions that may cause engine to run lean: Water intrusion in HO2S connector, exhaust leak between HO2S and engine, any vacuum leaks, incorrect fuel pressure, restricted fuel injectors, fuel contamination, or vacuum hoses that are split, kinked or improperly connected.
- Inspect for proper operation of the Manifold Absolute Pressure (MAP) sensor. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article.
- Inspect for proper operation of the Throttle Position (TP) sensor. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article.
- Inspect for a restricted air intake system.
- Use a scan tool in order to monitor the Knock Sensor (KS) system for excessive spark retard activity.
- Soak the secondary ignition system with water from a spray bottle. Soaking the secondary ignition system may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as water is applied.
- Inspect for proper ignition voltage output with a Spark Tester (J-26792).
- Remove spark plugs and inspect for correct heat range, wet plugs, cracks, wear, improper gap, burned electrodes or heavy deposits.
- An improper spark plug gap will cause a driveability problem. Gap spark plugs using a wire gauge gap tool.
- Determine cause of the fouling before replacing the spark plugs.
- Monitor the Misfire Current Counters while driving the vehicle within the conditions that the misfire occurred. If a misfiring cylinder can be located with a misfire, use DTC P0300 diagnostic procedures for diagnosis. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article.
- Inspect for loose ignition coil grounds.
- Inspect for excessive oil in the combustion chambers and leaking valve seals.
- Test for low cylinder compression.
- Inspect for incorrect basic engine parts, including camshaft, cylinder heads, and pistons, etc.
- Inspect exhaust system for possible restrictions.
- Inspect the transmission Torque Converter Clutch (TCC) for proper operation. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
- Inspect A/C system operation. The A/C clutch should cut out at the Wide Open Throttle (WOT) position.