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 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.
^ DEFECTIVE ELECTRONIC CONTROL UNIT:
^ ENGINE SPEED/REFERENCE SENSOR: Damaged
or improperly installed engine
speed/reference sensor.





FUEL CHECK: ^ FUEL PRESSURE: Fuel pump delivery volume
^ FUEL INJECTOR: Poor spray pattern, clogged, or
stuck.
^ AIR FLOW METER: Stuck or sluggish flap
^ DEFECTIVE ELECTRONIC CONTROL UNIT:
^ 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 rocker covers, inspect
for worn rocker arms, weak
valve springs or worn cam shaft lobes
^ RESTRICTIONS: Intake and exhaust system for
casting flash or other restrictions.