Symptom Definition

Cuts out, misses is defined as a steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. The exhaust may have a steady spitting sound at idle or low speed. Perform a careful visual inspection as described in BASIC TESTING article.

Possible Cause & Correction Check the following:

• Check ignition wires for short or faulty insulation.
• Check distributor cap for moisture, dust or cracks. Spray spark plug wires with a fine mist of water to check for shorts.
• Connect Spark Tester (ST-125) to spark plug and check for adequate spark.
• Check ignition system for faulty grounds.
• Ensure EST 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 or contaminated fuel.
• Check for improper fuel pressure.
• Check for EGR valve sticking open.
• Check ECM for proper ground circuits.
• Check TPS for sticking or binding. TPS voltage should be less than 1.25 volts at idle.
• Check for proper pick-up coil (HEI distributor) resistance.
• Check for restricted exhaust system. See Page 3 in BASIC TESTING article.
• Check for bent push rods, broken valve springs or worn camshaft lobes.