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 48 km/h (30 mph). The exhaust has a steady spitting sound at idle, low speed or on hard acceleration for fuel starvation that can cause engine to cut out.

IGNITION SYSTEM
^ Check for electrical missfire:
- Cracked Spark plug insulators
- Burned, worn, or improperly gapped electrodes
- Heavy deposits.
- Secondary ignition wires - excessive resistance or arcing to ground.
- Primary ignition fault. Refer to "DIAGNOSTIC CHARTS/C-CHARTS/CHART C-4M ELECTRONIC IGNITION (EI) SYSTEM MISFIRE DIAGNOSIS". Chart C-4M Electronic Ignition System Misfire Diagnosis

FUEL SYSTEM
^ Check fuel system - Plugged fuel fllter, low pressure. Refer to "DIAGNOSTIC CHARTS/A-CHARTS/ CHART A-7 FUEL SYSTEM DIAGNOSIS". Related Tests, Information and Procedures
^ Check Contaminated fuel.
^ Check injector drivers. Disconnect all injector harness connectors. Connect J-34730-2 Injector Test Light or equivalent between the harness terminal of each injector connector and note light while cranking. If test light fails to blink at any one of the connectors, it is a faulty injector drive circuit harness, connector, or terminal.
^ Check perform the "Injector Coil/Balance Test." Refer to "DIAGNOSTIC CHARTS/C-CHARTS/CHART C-2A FUEL INJECTOR TESTING". Chart C-2A Fuel Injector Balance Test

ENGINE MECHANICAL
^ Check compression - Perform compression check on questionable cylinder(s) found above. If compression is low, repair as necessary.
^ Check base engine - worn camshaft lobes and valve timing. Repair as necessary

ADDITIONAL CHECKS
^ EMI interference. A missing condition can be caused by Electromagnetic Interference (EMI) on the reference circuit. EMI can usually be detected by monitoring engine RPM with a Tech-1 scan tool. A sudden increase in RPM with little change in actual engine RPM change, indicates EMI is present.
^ Intake and exhaust manifold passage for casting flash.