Possible Causes & Corrections

Check the following items:

• Check for restricted exhaust system. See EXHAUST SYSTEM BACKPRESSURE under MECHANICAL INSPECTION in appropriate BASIC DIAGNOSTIC PROCEDURES article.
• Monitor the Misfire Current Counters while driving the vehicle in the conditions that the misfire occurred. If a cylinder can be located with a misfire, see appropriate SELF-DIAGNOSTICS article.
• Check engine compression. Check for incorrect valve timing, bent push rods, broken valve springs or worn camshaft lobes.
• Using Spark Tester (J-26792), check for adequate spark at spark plugs.
• Check ignition system for faulty ground and power feed circuits.
• Check for proper Crankshaft Position (CKP) and Camshaft Position (CMP) sensor resistance.
• Remove spark plugs and check for wet plugs, cracks, improper gap, burned electrodes or heavy carbon deposits. Also, check condition of spark plug wires. Spray spark plug wires with a fine mist of water to check for shorts.
• Check Transaxle Range (TR) switch input with vehicle in drive and shifter in drive or overdrive.
• Check for poor quality or alcohol contaminated fuel.
• Check fuel injectors. Perform injector balance test. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
• Check fuel system for incorrect fuel pressure. See BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
• Inspect items that cause an engine to run rich, long term fuel trim near -13 percent.
• Inspect items that can cause an engine to run lean, long term fuel trim near 24 percent.
• Check PCM grounds. Ensure they are clean, tight and properly located.
• Check TP sensor for sticking and binding. Check for correct TP sensor voltage. See FUEL SYSTEMS in appropriate SERVICE & ADJUSTMENT SPECIFICATIONS article.
• Use a scan tool in order to monitor the Knock Sensor (KS) system for excessive spark retard activity.