Isuzu 1999 RODEO Workshop Manual page 991

6E1–364 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
ROUGH, UNSTABLE, OR INCORRECT
IDLE, STALLING SYMPTOM
DEFINITION:
Engine runs unevenly at idle. If severe, the engine or
vehicle may shake. Engine idle speed may vary in RPM.
Either condition may be severe enough to stall the engine.
Step
1 Was the On–Board Diagnostic (OBD) System Check
performed?
2 1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
3 Was a visual/physical check performed, including the
rotor, ignition coil and secondary ignition wires?
4 Verify that the EGR valve is not mounted backwards.
Was a problem found?
5 1. Check for incorrect idle speed. Ensure that the
following conditions are present:
f
Engine fully warm.
f
Accessories are OFF.
2. Using a Tech 2, monitor IAC position.
Is the IAC position within the specified values?
6 1. Visually/physically
conditions:
f
Restricted air intake system. Check for a
restricted air filter element, or foreign objects
blocking the air intake system.
f
Check for objects blocking the IAC passage or
throttle bore, excessive deposits in the IAC
passage and on the IAC pintle, and excessive
deposits in the throttle bore and on the throttle
plate.
f
Check for a condition that causes a large
vacuum leak, such as an incorrectly installed
or faulty crankcase ventilation valve brake
booster hose.
Was a problem found?
7 Using a Tech 2, monitor TP angle with the engine idling.
Is the TP angle at the specified value and steady?
8 Check for proper ignition voltage output with the spark
tester J 26792.
Was a problem found?
9 1. Remove the spark plugs and check for gas or oil
fouling, cracks, wear, improper gap, burned
electrodes, heavy deposits or improper heat range.
2. If spark plugs are fouled, the cause of the fouling
must be determined before replacing the spark
plugs.
Was a problem found?
Action
inspect for the following
Value(s) Yes
— Go to Step 2
— Verify repair
— Go to Step 4
— Verify repair
Between 10
and 50
counts Go to Step 8
— Verify repair
0% Go to Step 8
— Verify repair
— Verify repair
No
Go to OBD
System
Check
Go to Step 3
Go to Visual /
Physical
Check
Go to Step 5
Go to Step 7
Go to Step 7
For further
diagnosis,
refer to DTC
P0123
Go to Step 9
Go to Step 10