Possible Causes & Corrections

Check the following items:

• Fuel system circuits for proper operation. Refer to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS in FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
• Low fuel pressure. Refer to FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
• Faulty fuel injectors. Refer to FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 3.4L AZTEK & RENDEZVOUS article.
• 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.
• Inspect spark plugs for proper heat range and reach.
• Inspect for proper ignition voltage output using Spark Tester (J-26792).
• If spark is not present at the coils, inspect ignition coil for cracks, carbon tracking/arcing, coil resistance value out of 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 out of 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.
• Low engine coolant.
• Restricted air flow to radiator or restricted water flow through the radiator.
• Inoperative electric cooling fan circuits.
• Correct coolant solution should be a 50/50 mix.
• Excessive oil in combustion chamber or leaking valve seals.
• Low cylinder compression. Refer to MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
• Incorrect basic engine parts. Inspect cylinder heads, camshaft, valve train components, pistons, etc.
• 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.
• Test for proper EGR system operation. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.
• Inspect the Transaxle Range Switch input with the vehicle in Drive and gear selector in Drive or Overdrive. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
• Test the Torque Converter Clutch (TCC) operation. TCC applying too soon can cause engine to spark knock.
• If scan tool readings are normal and there are no engine mechanical faults, fill the fuel tank with a known-good quality gasoline that has a minimum octane rating of 87 and re-evaluate vehicle performance.