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 ACTION



IGNITION CHECK: ^ CYLINDER MISFIRE
1. Start engine, allow engine to warm-up.
Shut off engine, disconnect idle speed stepper
motor, idle speed actuator motor, or
SOLE-VAC Throttle Positioner, restart engine.
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), proceed to
STALLS, ROUGH, UNSTABLE OR INCORRECT IDLE.
Reconnect idle speed stepper or idle speed
actuator motor with ignition "OFF."

CAUTION: Do not perform this test for more than 2 minutes.
Damage to the catalytic converter will result.

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 no spark, refer to Testing and Inspection/Procedures.
If there is spark, remove the spark plug(s)
in these cylinders and check for:
^ Insulation Cracks
^ Wear
^ Improper Gap
^ Burned Electrodes
^ Heavy Deposits
^ SPARK PLUG RESISTANCE
Resistance should not exceed 30,000 ohms.
Check the rotor and distributor cap.
NOTE: If the previous checks did not locate 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.
^ ALTERNATOR
Verify the alternator voltage output, and all diodes.







FUEL CHECK: ^ FUEL PRESSURE.

^ FUEL QUALITY.
Restricted fuel filter or contaminated fuel.



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