hello, are you using or losing any engine coolant?tim
has any other sensors been replaced such as the cam and or crank sensor?
fuel pressure checked?
did this happen all at once?tim
i will give you this diagnopstic flow chart-- hopefully you will be able to use your scan tool to follow through with the diagnosis,tim
ENGINE MECHANICAL PROBLEM
FUEL SYSTEM PROBLEM
ERRATIC CAM/CRANK SENSOR SIGNALS
OTHER POSSIBLE CAUSES FOR MIS-FIRE
With the scantool, select DTCs and RELATED FUNCTIONS. Read and record the
FREEZE FRAME DATA. Select OBD II MONITORS. Read and record the MIS-FIRE
SIMILAR CONDITIONS WINDOW DATA.
With these screens, attempt to duplicate the condition(s) that has set this DTC.
When the vehicle is operating in the SIMILAR CONDITIONS WINDOW, refer to the
WHICH CYLINDER IS MISFIRING screen.
Observe the WHICH CYLINDER IS MISFIRING screen for at least one minute.
Is the scantool counting mis-fires at this time?
Yes ! Go To 2
No ! Go To 8
2 With the scantool, read the FREEZE FRAME DATA.
Use the FREEZE FRAME DATA and attempt to determine the cause of the Misfire
In the FREEZE FRAME DATA, is the LOAD VALUE over 50% and the operating
Yes ! Check secondary ignition components and perform a cylinder
Perform FUEL SYSTEM/MISFIRE MONITOR VERIFICATION
No ! Go To 3
3 Check for any of the following conditions/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
CYLINDER LEAKAGE TEST - must be within specifications
CAM LOBES - must not be worn excessively
WEAK or BROKEN VALVE SPRINGS
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL INJECTOR - plugged or restricted injector; control wire not connected to
Are there any engine mechanical problems?
Yes ! Repair as necessary.
No ! Go To 4
4 With the scantool, read the FREEZE FRAME DATA.
In the FREEZE FRAME, are the adaptive fuel percentages greater than +/- 15%?
Yes ! perform the Checking Fuel
No ! Go To 5
With the scantool, read the FREEZE FRAME DATA.
In the FREEZE FRAME DATA, is the engine RPM over 3000 and the operating temp
Yes ! Test CMP and CKP signals with Lab Scope, check valve timing,
and perform running vacuum test.
No ! Go To 6
The following are other possible causes for mis-fire:
Injector harness connectors, PCM power grounds, restricted exhaust, intake restriction,
damaged trigger wheel, contaminated fuel, carbon build up on valves, or the
accessory drive belt (serpentine belt).
Do any of the above causes exist?
No ! Go To 7
7 If there are no possible causes remaining, view repair. All
Replace and program the Powertrain Control Module in accordance
with the Service Information.
8 NOTE: The conditions that set the DTC are not present at this time.
An intermittent problem may have been caused by moisture in the secondary
WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS, OR FAN. DO NOT WEAR LOOSE CLOTHING.
With the scantool, select DTC's AND RELATED FUNCTIONS. Read and record the
FREEZE FRAME DATA. Select OBD II MONITORS. Read and record MIS-FIRE
With these screens, attempt to duplicate the condition that has set the Misfire DTC.
While using FREEZE FRAME DATA, pay particular attention to the DTC setting
conditions, such as speed, temp, load, and map vacuum.
Does the mis-fire reoccur?
Yes ! Restart diagnostics beginning with Test 2.
No ! Test Complete
please let me know if this helps,tim
well, as stated -- some are with just the key on -- the engine mechanical side -- vac etc -- are at idle---electrical connections are engine off key on,tim
if i had to guess- based on what i have seen -- i would pay close attention to the pcm wiring -- and also do a compression test to see if we have internal mechanical issues first,tim
goodluck and let me know how you make out,tim