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 for the following items:

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Monitor the Heated Oxygen Sensors (HO2S). See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. The HO2S should respond quickly to different throttle positions. If not, inspect the HO2S for Silicone or other contaminants from fuel or use of improper RTV sealant. The sensors may have a White powdery coating. Silicone contamination causes a high but false HO2S signal voltage, rich exhaust indication. The PCM will reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
Monitor the 24X crank sensor and CMP sensor signal present parameters on scan tool. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP "A" and CMP sensor circuits for intermittents.
Monitor the 3X crank sensor parameter on scan tool. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. If the 3X crank sensor parameter is not responding, inspect the CKP sensor "B" and circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the 3X low reference circuit for intermittents. If these circuits become open or shorted they may not set a DTC immediately, but are capable of causing driveability complaints.
Test the CKP sensor "B" for an internal short. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
Inspect Throttle Position (TP) sensor and related wiring. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
Inspect Mass Airflow (MAF) sensor and related wiring. 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 MAF sensor and the throttle body.
Test the EGR system for proper operation.
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, a long term fuel trim is significantly in the negative range.
Inspect any items which may cause an engine to run lean. Using scan tool, a long term fuel trim is significantly in the positive range.
Inspect for proper ignition voltage output using Spark Tester (J-26792).
If spark is not present at the coils, inspect for 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