Isuzu 1999 RODEO Workshop Manual page 832

DTC P0303 – Random/Multiple Cylinder Misfire Detected
Step
1 Was the "On–Board Diagnostic (OBD) System Check"
performed?
2 1. Start and idle the engine.
2. Review and record the Tech 2 Freeze Frame data.
3. Operate the vehicle to duplicate the conditions
present when the Diagnostic Trouble Code was set
(as defined by the Freeze Frame data).
4. Monitor the Tech 2 "Misfire Cur. #" display for each
cylinder.
Is "Misfire Cur. #" display increasing for any cylinder
(indicating a misfire currently occurring)?
3 1. Visually and physically inspect the vacuum hoses
for splits, kinks, and improper connections.
2. If a problem is found, repair or replace the vacuum
hoses as necessary.
Did your inspection reveal a problem?
4 1. Visually and physically inspect the following areas
for vacuum leaks:
f
Intake manifold
f
Injector O–rings
f
EGR valve
f
EGR feed pipes
Did your inspection reveal a vacuum leak?
5 Inspect the crankcase ventilation valve for proper
installation or a cracked hose.
Did your inspection reveal a problem?
6 1. Remove and visually/physically inspect the ignition
coils. Ensure that the coils are free of cracks and
carbon tracking.
2. If a problem is found, replace the damaged ignition
coils.
Was a problem found?
7 1. Install a spark tester at the spark plug end of the
ignition wire for the cylinder that is indicated by the
"Misfire Cur. Counters" or "Misfire Hist. Counters"
as having the most severe misfire (largest number
of counts).
2. Crank the engine while observing the spark tester. A
crisp, blue spark should be observed.
Is adequate spark present?
8 1. Remove the spark plugs from the cylinders that
were indicated as misfiring.
2. Visually inspect the spark plug electrodes.
Does your inspection reveal any spark plugs exhibiting
excessive fouling?
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
Action Value(s) Yes
— Go to Step 2
— Go to Step 3
— Verify repair
— Verify repair
— Verify repair
— Verify repair
Go to Step
— 12
Go to Engine
Mechanical
— Diagnosis
6E1–205
No
Go to OBD
System
Check
Refer to
Diagnostic
Aids
Go to Step 4
Go to Step 5
Go to Step 6
Go to Step 7
Go to Step 8
Go to Step 9