TEST ACTION APPLICABILITY
12 Engine Off.
Connect a suitable engine analyzer to the engine.
Allow the Engine to idle.
NOTE: If the Engine will not idle, maintain a constant RPM above idle.
NOTE: Set the scope to read display or parade pattern.
Remove any spark plug wire.
Observe the Secondary KV Line.
Is the open secondary voltage at least 25 KV?All
Ye s®Go To 13
No®Replace the Ignition Coil.
Perform VERIFICATION TEST VER-5A2.
13 Engine Off.
Connect a suitable engine analyzer to the engine.
Allow the Engine to idle.
NOTE: If the Engine will not idle, maintain a constant RPM above idle.
NOTE: Set the scope to read display or parade pattern.
Follow the equipment manufacturer's procedure for pattern analysis.
Is the secondary ignition pattern OK?All
Ye s®Go To 14
No®Repair the indicated component in the Secondary Ignition Sys-
tem.
Perform VERIFICATION TEST VER-5A2.
14 The following are possible causes for mis-fire:
Injector harness connectors, ignition coil circuit, spark plug, mechanical engine
problem, PCM power grounds, irregular cam and crank signal, injectors, restricted
exhaust, intake restriction, PCM, Evap System, EGR System, damaged trigger
wheel, and
accessory drive belts.
Do any of the above causes exist?All
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Go To 15
15The following additional items should be checked as possible mechanical
problems:
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions
ENGINE PCV SYSTEM - must flow freely
ENGINE DRIVE SPROCKETS - must be properly positioned
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connected to
correct injector
Are there any engine mechanical problems?All
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Test Complete.
103
DRIVEABILITY
P-0300 MULTIPLE CYLINDER MIS-FIRE ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
12 Engine Off.
Connect a suitable engine analyzer to the engine.
Allow the Engine to idle.
NOTE: If the Engine will not idle, maintain a constant RPM above idle.
NOTE: Set the scope to read display or parade pattern.
Follow the equipment manufacturer's procedure for pattern analysis.
Is the secondary ignition pattern OK?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Go To 13
No®Repair the indicated component in the Secondary Ignition Sys-
tem.
Perform VERIFICATION TEST VER-5A2.
13 With the DRB, read the FREEZE FRAME DATA.
Use the freeze frame data and attempt to determine the cause of the misfire.
In the FREEZE FRAME, is the ENGINE RPM over 3000 and the operating temp
normal?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Lab scope cam and crank sensor, check valve timing, running
vacuum test.
Perform VERIFICATION TEST VER-5A2.
No®Go To 14
14The following additional items should be checked as possible mechanical
problems:
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions
ENGINE PCV SYSTEM - must flow freely
ENGINE DRIVE SPROCKETS - must be properly positioned
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connected to
correct injector
Are there any engine mechanical problems?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Go To 15
15 The following are other possible causes for mis-fire:
Injector harness connectors, ignition coil circuit, spark plug, mechanical engine
problem, PCM power grounds, irregular cam and crank signal, injectors, restricted
exhaust, intake restriction, PCM, Evap System, EGR System, damaged trigger
wheel, and
accessory drive belts.
Do any of the above causes exist?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Test Complete.
107
DRIVEABILITY
P-0305 CYLINDER #5 MIS-FIRE ÐContinued
ProCarManuals.com
