Page 1491 of 2100

6E±524
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Dieseling, Run-On Symptom
StepActionValue(s)Ye sNo
1DEFINITION:
Engine continues to run after key is turned ªOFF,º but
runs very rough. If engine runs smooth, check ignition
switch and adjustment.
Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. 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?
ÐVerify repairGo to Step 3
3Was a visual/physical check performed?
ÐGo to Step 4
Go to Visual/
Physical
Check
41. Check for a short between B+ and any of the ignition
feed circuits.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 5
51. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Tech 2 data
Freeze Frame data/Failure Records butter
All electrical connections within a suspected
circuit and/or system
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Contact
Technical
Assistance
Page 1493 of 2100

6E±526
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Backfire Symptom
StepNo Ye s Value(s) Action
91. Check for the following engine mechanical
conditions.
Refer to
Engine Mechanical for diagnosis
procedures:
Low compression
Sticking or leaking valves
Worn camshaft lobe(s)
Camshaft drive belt slipped or stripped
Incorrect valve timing
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 10
101. Check the intake and exhaust manifold(s) for
casting flash. Refer to
Engine Mechanical.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
111. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Tech 2 data
Freeze Frame data/Failure Records butter
All electrical connections within a suspected
circuit and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Contact
Technical
Assistance
Page 1496 of 2100

6E±529
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Cuts Out, Misses Symptom
StepNo Ye s Value(s) Action
201. Check the PCV valve for proper operation. Refer to
Crankcase Ventilation System.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 21
211. Check the transmission range switch circuit. Use a
Tech 2 and be sure the Tech 2 indicates that the
vehicle is in drive with the gear selector in drive or
overdrive.
2. If a problem is found, diagnose and repair the
transmission range switch as necessary (refer to
4L30-E Automatic Transmission Diagnosis).
Was a problem found?
ÐVerify repairGo to Step 22
221. Check the following engine mechanical items.
Refer to
Engine Mechanical for diagnosis
procedures:
Low compression
Sticking or leaking valves
Worn camshaft lobe(s)
Camshaft drive belt slipped or stripped
Incorrect valve timing
Worn rocker arms
Broken valve springs
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 23
231. Check for faulty motor mounts. Refer to Engine
Mechanical
for inspection of mounts.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 24
241. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Tech 2 data
Freeze Frame data/Failure Records butter
All electrical connections within a suspected
circuit and/or system
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Contact
Technical
Assistance
Page 1499 of 2100
6E±532
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Hesitation, Sag, Stumble Symptom
StepNo Ye s Value(s) Action
171. Visually/physically check vacuum hoses for splits,
kinks, and proper connections and routing as
shown on the ªVehicle Emission Control
Informationº label.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 18
181. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Tech 2 data
Freeze Frame data/Failure Records butter
All electrical connections within a suspected
circuit and/or system
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Contact
Technical
Assistance