Cuts Out/Misses

Definition: Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. Not normally felt above 1500 RPM or 30 MPH (48 km/h). The exhaust has a steady splitting sound at idle or low speed.

^ Perform "Diagnostic Circuit Check - Calif."

^ Perform "System Performance Check - Calif".

^ Visual (Physical) Check:

- Vacuum hoses for splits, kinks, and proper connections as shown on Vehicle Emission Control Information label.

- Ignition wires for proper firing order, cracking, hardness and proper connections at both distributor cap and spark plugs.

- Wiring for proper connections, pinches and cuts.

^ Check spark plug wire routing for correct firing order.

^ Check ignition system for misfiring spark plug:

1. Disconnect and plug air cleaner and EGR vacuum hoses.

2. Remove one spark plug wire at a time using insulated pliers.

3. If there is no RPM drop on one or more cylinders, or excessive variation in drop, check for spark on the suspected cylinder(s) with ST 125 spark cap tool or equivalent.

4. If no spark when checking with J26792 (ST 125), check spark plug wires by connecting ohmmeter to ends of each wire in question. If meter reads over 30,000 OHMS, replace wire(s).


^ If spark with J26792 (ST 125), check spark plug and compression for that/those cylinder(s).

^ Visually check distributor cap inside and out for moisture, dust, cracks, burns and check for arcing to coil mounting screws. With engine running, spray cap and plug wires with fine water mist to check for shorts.

^ Check for loss of ground, or intermittent ground, in integral ignition coil.

^ Check EGR valve for sticking partially open.

^ Remove spark plugs and check for cracks, wear, improper gap, burned electrodes, or heavy deposits.

^ Remove rocker covers. Check for bent pushrods, worn rocker arms, broken valve springs, worn camshaft lobes, repair as necessary.