Possible Causes & Corrections

WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

Check the following items:

Search for bulletins.
Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis in FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
Test for low fuel pressure. Refer to FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
Test for faulty fuel injectors. Refer to FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
Inspect for fuel contamination.
Inspect any items which may cause an engine to run rich. Using scan tool, long term fuel trim is significantly in the negative range.
Inspect any items which may cause an engine to run lean. Using scan tool, long term fuel trim is significantly in the positive range.
Test the CKP sensor "B" for an internal short. Refer to Electronic Ignition System in IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
Using a scan tool, monitor Knock Sensor (KS) system for excessive spark retard activity. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
If knock retard is greater than 10-12 degrees, disconnect KS, and ground the sensor harness connector. Monitor knock retard on scan tool. There should be no knock retard present. If knock retard is still present, replace PCM.
Inspect EGR system for proper operation. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the Mass Airflow (MAF) sensor and throttle body.
Inspect for proper ignition voltage output using Spark Tester (J-26792).
If spark is not present at the coils, inspect coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range (5000-8000 ohms). Check spark plug wires for signs of arcing, crossfiring, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range (3000 ohms per foot). Check for defective ignition module, ignition system wiring, loose ignition module feed or ground connection, or damaged system wiring.
Remove spark plugs and inspect for fouled plugs, cracks, wear, improper gap, burned or damaged electrodes, improper heat range or reach.
If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
Excessive oil in combustion chamber, caused by leaking valve seals.
Low cylinder compression. Refer to MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
For incorrect basic engine parts such as cylinder heads, camshaft, valve train components, pistons, etc.
Inspect the exhaust system for any possible restrictions. Inspect exhaust system for damaged or collapsed pipes. Inspect mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converter. Test for proper Torque Converter Clutch (TCC) operation. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.