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.
^ 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.