Possible Cause & Correction
Check following items:
- Check ignition wires for short or faulty insulation.
- Check distributor cap (if equipped) for moisture, dust or cracks. Spray spark plug wires with a fine mist of water to check for shorts.
- Using Spark Tester (J-26792), check for available secondary voltage.
- Check ignition system for faulty grounds.
- Ensure ignition control wiring harness is not routed too close to wiring which may cause induced voltage signals.
- Check ignition coil connections.
- Remove spark plugs and check for correct heat range, wear, cracks, wetness, improper gap or heavy deposits.
- Check for poor quality or water contaminated fuel.
- Check for improper fuel pressure. Check for restricted fuel filter.
- Check for plugged injectors. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article.
- Check PCM for proper ground circuits. Check for internal PCM intermittents.
- Check for bent push rods, broken valve springs or worn camshaft lobes.
- Check for EGR valve sticking open.
- Check TP sensor for sticking and binding. Check for correct TP sensor voltage. See THROTTLE POSITION (TP) SENSOR under FUEL SYSTEM in appropriate SERVICE & ADJUSTMENT SPECIFICATIONS article.
- Check for proper crankshaft position sensor resistance.
- Check for restricted exhaust system.
- Check injector drivers by disconnecting all injector harness connectors and connecting a 6-volt test light to each injector's harness terminal. Light should blink while cranking.
- Check engine compression. Check for incorrect valve timing.
- Check intake and exhaust manifold passages for casting flash.
- Check distributor vent system (if equipped).