Isuzu 1999 RODEO Workshop Manual page 985

6E1–358 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
SURGES AND/or CHUGGLES SYMPTOM
DEFINITION:
Engine power variation under steady throttle or cruise.
Feels like the vehicle speeds up and slows down with no
change in the accelerator pedal.
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?
4 Be sure that the driver understands A/C compressor
operation as explained in the owner's manual. Inform
the customer how the A/C clutch operate.
Is the customer experiencing a normal condition?
5 Check the fuel control Heated Oxygen Sensor
(HO2S1). When monitored on the Tech 2, the H02S1
should respond quickly to different throttle positions. If
it doesn't check for silicon or other contaminants from
fuel or use of improper RTV sealant. The sensors may
have a white powdery coating. Silicone contamination
sends a rich exhaust signal which causes the PCM to
command an excessively lean air/fuel mixture.
Was a problem found?
6 Check the fuel pressure. Refer to Fuel System
Pressure Test.
Was a problem found?
7 Monitor "Long Term Fuel Trim" on the Tech 2.
Is "Long Term Fuel Trim" in the negative range (rich
condition)?
8 Check items that can cause the engine to run rich.
Refer to Diagnostic Aids in DTC P0172.
Was a problem found?
9 Check items that can cause the engine to run lean.
Refer to Diagnostic Aids in DTC P0171.
Was a problem found?
10 Check for proper ignition voltage output with the spark
tester J 26792.
Was a problem found?
11 Check for a loose ignition control module ground.
Was a problem found?
Action Value(s) Yes
— Go to Step 2
— Verify repair
— Go to Step 4
— System OK
— Verify repair
— Verify repair
— Go to Step 8
— Verify repair
— Verify repair
— 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 6
Go to Step 7
Go to Step 9
Go to Step 10
Go to Step 10
Go to Step 11
Go to Step 12