Cuts Out/Misses

SYMPTOM DESCRIPTION:

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.

SYSTEM OR COMPONENT TO CHECK

IGNITION
CHECK:
CYLINDER MISS:
1. Start engine, allow engine to warm-up. Remove one spark plug wire at a time, using insulated pliers.
2. If there is an rpm drop, on all cylinders, (equal to within 50 rpm), go to STALLS, ROUGH, UNSTABLE OR INCORRECT IDLE:

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

3. If there is no rpm drop on one or more cylinders, or an excessive variation in drop, check for spark on the suspected cylinder(s)
If there is no spark, check the wire, distributor cap, and rotor for leaks or shorts.
If there is spark, remove spark plug(s) in these cylinders and check for: Insulation Cracks, Wear, Improper Gap, Burned Electrodes, Heavy Deposits

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

IGNITION CONTROL UNIT: Defective
CRANKSHAFT POSITION/SPEED SENSOR: Damaged or improperly installed sensor

FUEL
CHECK:
FUEL PRESSURE: Fuel pump delivery volume
FUEL INJECTOR: Poor spray pattern, clogged, or stuck
FUEL QUALITY: Contaminated fuel or incorrect octane rating.

ENGINE
CHECK:
COMPRESSION: Perform a compression check and cylinder leak down test.Look for low compression, sticking or leaking valves.
VALVE TIMING: Remove valve covers, inspect for weak valve springs or worn cam shaft lobes
RESTRICTIONS: Intake and exhaust system for casting flash or other restrictions.