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 for the following items:
- Search for bulletins.
- Verify that PCM grounds are clean, tight and in the proper locations.
- Inspect the Manifold Absolute Pressure (MAP) sensor operation. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article.
- Inspect Oxygen Sensor No. 1 (O2S 1). The O2S 1 should respond quickly to different throttle positions. If not, inspect the O2S 1 for silicone or other contaminants from fuel or the use of improper RTV sealant. The sensors may have a White powdery coating. Silicone contamination causes a high but false O2S 1 signal voltage, a rich exhaust indication. The PCM will reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
- 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 proper operation of the Engine Coolant Temperature (ECT) sensor. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article.
- 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 the engine to run rich: Water intrusion in HO2S connector, engine oil contaminated by fuel, an 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 the engine to run lean: Water intrusion in HO2S connector, exhaust leak between the HO2S and engine, vacuum leaks, incorrect fuel pressure, restricted fuel injectors, fuel contamination, or vacuum hoses that are split, kinked or improperly connected.
- 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 you apply water.
- Test for proper ignition voltage output with a Spark Tester (J-26792).
- Remove spark plugs and check 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 fouling before replacing spark plugs.
- Monitor the Misfire Current Counters while driving vehicle in the conditions that the misfire occurred. If a misfiring cylinder can be located, use the DTC P0300 diagnostic procedures. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article.
- Inspect for loose ignition coil grounds.
- Inspect engine thermostat for proper operation and for proper heat range.
- Inspect generator output voltage. Repair charging system if generator output voltage is less than 9 volts or more than 16 volts.
- Inspect for proper operation of the automatic transmission.