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 (ST-125), 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. See INJECTOR BALANCE TEST in SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
• 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. TP sensor voltage should be less than 1.25 volts at idle.
• Check for proper crank angle sensor (DIS and IDI) or pick-up coil (HEI distributor) 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).