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.
Shut off engine, disconnect IAC motor,
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), go to
STALLS, ROUGH, UNSTABLE OR INCORRECT IDLE.
Reconnect IAC motor with ignition "OFF."
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)
with J 26792 (ST-125) Spark Tester or equivalent.
If no spark, refer to COMPONENT TESTING (C-CHARTS).
If there is spark, remove spark plug(s)
in these cylinders and check for:
^ Insulation Cracks
^ Wear
^ Improper Gap
^ Burned Electrodes
^ Heavy Deposits
^ SPARK PLUG WIRES. Resistance should not
exceed 30,000 ohms, also check rotor
and distributor cap.
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 CHECK: ^ FUEL PRESSURE.
Refer to DIAGNOSTIC CHARTS/A-CHARTS
^ 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.