Cuts Out/Misses

DEFINITION
Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. The exhaust has a steady spitting sound at idle or low speed.

PRELIMINARY CHECKS
^ Perform the careful "Visual And Physical Checks" in Preliminary Checks. - Important Preliminary Checks

IGNITION SYSTEM
Check for cylinder miss by starting engine, allow engine to stabilize.
1. Remove one spark plug wire at a time, using insulated pliers.

CAUTION: Do not perform this test for more than 2 minutes, as this may cause damage to the three way catalytic converter.

2. If there is an rpm drop, on all cylinders (equal to within 50 rpm), refer to Rough, Unstable Or Incorrect Idle, Stalling. Rough, Unstable, or Incorrect Idle, Stalling
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 J 26792 or equivalent. If no spark, refer to On-Board Diagnostic System Check. Testing and Inspection

If there is spark, remove spark plug(s) in these cylinders and check for:
^ Insulation Cracks
^ Wear
^ Improper Gap
^ Burned Electrodes
^ Heavy Deposits

Check spark plug wire resistance (should not exceed 3,000 - 6700 ohms per foot); also, check ignition and connections.

NOTE: If the previous checks did not find the problem, visually inspect ignition system for moisture, dust, cracks, burns, etc. With engine running, spray plug wires with fine water mist to check for shorts.

FUEL SYSTEM
^ Check fuel pressure.
Refer to Chart A-7B Fuel Pressure Check. Testing and Inspection

Also, refer to On-Board Diagnostic System Check. Testing and Inspection

^ Check for contaminated fuel or restricted fuel filter.

ENGINE MECHANICAL
^ Check for proper valve lash adjustment.
^ Check for low compression.
^ Check intake and exhaust manifold passages for casting flash.