2001 Dodge Dakota Truck idles rough and misfires

Tiny
RANK
  • MEMBER
  • 2001 DODGE DAKOTA
  • V8
  • 2WD
  • AUTOMATIC
  • 178,000 MILES
I recently purchased a 2001 dodge dakota, 4.7-v8-- and I have had nothing but trouble. The engine light flickers constantly, and when I run the codes it keeps saying that cylinders 3 and 4 are misfiring. I have replaces all the injectors, coils, spark plugs, map sensor and cam sensor, and the same cylinders keep coming up. I have almost no power going up hills, because of the misfiring-and the truck idles terribly, when I stop the truck just dies. I am now going to put a new fuel pump in-- can any-one help me out? I am thinking of buying another truck, or another engine-- I can't drive this truck as it is-- Thanks!
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Tuesday, February 3rd, 2009 AT 11:27 AM

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Tiny
ZACKMAN
  • MEMBER
In order to the test, you have to have a scan tool with Freeze Frame function.

Testing

1. Turn ignition on with engine off. Using scan tool, check for DTCs. If MISFIRE GOOD TRIP counter is displayed and equal to zero, go to next step. If MISFIRE GOOD TRIP counter is not displayed and equal to zero, go to step 4.

2. At this time, conditions required to set DTC exist. Using scan tool, read FREEZE FRAME data and MISFIRE SIMILAR CONDITIONS WINDOW data while operating vehicle in the same conditions in which DTC was set. When in SIMILAR CONDITIONS WINDOW, go to WHICH CYLINDER IS MISFIRING monitor on scan tool. If scan tool is not counting misfires at this time, test is complete. At this time, misfire does not exist or is an intermittent problem. If scan tool is counting misfires at this time, go to next step.

3. Using scan tool, read FREEZE FRAME data and attempt to determine the cause of misfire. In FREEZE FRAME data, note the adaptive fuel percentages. If adaptive fuel percentages are not more than 15 percent plus or minus, go to step 7. If adaptive fuel percentages are more than 15 percent plus or minus, fuel pressure and fuel pump volume must be checked. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

4. At this time, conditions required to set DTC exist. Using scan tool, read FREEZE FRAME data and MISFIRE SIMILAR CONDITIONS WINDOW data while operating vehicle in the same conditions in which DTC was set. When in SIMILAR CONDITIONS WINDOW, go to WHICH CYLINDER IS MISFIRING monitor on scan tool. If misfires do not reoccur, test is complete. At this time, misfire does not exist or is an intermittent problem. If misfires reoccur, go to next step.

5. Using scan tool, read FREEZE FRAME data and attempt to determine the cause of misfire. In
FREEZE FRAME data, note the adaptive fuel percentages. If adaptive fuel percentages are not more than 15 percent plus or minus, go to next step. If adaptive fuel percentages are more than 15
percent plus or minus, fuel pressure and fuel pump volume must be checked. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

6. Using scan tool, read ENGINE RPM under FREEZE FRAME data. If engine RPM is 3000 RPM or less and engine coolant temperature is not within normal operating range, go to next step. If engine RPM is more than 3000 RPM and engine coolant temperature is within normal operating range, use lab scope to test camshaft and crankshaft position sensors, check engine valve timing and engine vacuum. Perform TEST VER-7.

7. Check following items for possible causes of a cylinder misfire.
Check engine vacuum. Engine vacuum must be at least 13 in. Hg with transmission in Neutral.
Check engine valve timing.
Check engine compression.
Check exhaust system for restrictions.
Ensure PCV system is functioning properly.
Check torque converter stall speed.
Check power brake booster for internal vacuum leak.
Check fuel for contamination.
Check for defective fuel injector wiring harness, connectors or fuel injectors.
If any of the problems listed exist, repair as necessary. Perform TEST VER-7. If none of the
problems listed exist, go to next step.

8. Using scan tool, read LOAD VALUE under FREEZE FRAME data. If load value is 50 percent or less and engine coolant temperature is not within operating range, go to next step. If load value is more than 50 percent and engine coolant temperature is within normal operating range, check secondary ignition system, compression and cylinder leakage. Perform TEST VER-7.

9. Check for following additional items for possible mechanical problems which may cause a misfire.
Injector Harness Connectors
Secondary Ignition
Engine Mechanical Problem
PCM Power And Grounds
Irregular Cam Or Crank Signal
Intake Restriction
Damaged Trigger Wheel
Vacuum Leaks
Carbon Deposits On Valves

If any of the causes listed exist, repair as necessary. Perform TEST VER-7. Test is complete.

***To perform this test, you have to have scan tool capable of ABS and SRS systems. This test is designed to be used with Chrysler DRB scan tool***

TEST VER-7: FUEL/MISFIRE VERIFICATION
Programming PCM & Clearing DTCs From ABS & SRS Modules

NOTE: If Powertrain Control Module (PCM) was replaced, the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent DTCs from being stored Anti-Lock Brake System (ABS) module and Supplemental Restraint System (SRS) module. To program PCM and clear DTCs from ABS and SRS modules, proceed to appropriate procedure.

Connect scan tool to Data Link Connector (DLC). Using scan tool, enter correct VIN and mileage into
PCM. Using scan tool manufacturer's instructions, clear DTCs from ABS and SRS modules. Proceed to
final procedure.

Final Procedure

1. Inspect vehicle to ensure all components related to the repair are properly connected. Reassemble
and reconnect components as necessary. If all DTCs have been diagnosed and repaired, go to next step. If any DTCs have not been diagnosed, perform appropriate DTC test and finish diagnosing remaining DTCs as necessary.

NOTE: Ensure misfire detection is enabled if a repair procedure was performed for a misfire DTC. A low fuel condition or an unlearned adaptive numerator can disable the misfire monitor. If PCM has been
replaced or disconnected during testing, the adaptive numerator must be relearned in order for misfire monitor to run.

2. Using scan tool, monitor SIMILAR CONDITIONS WINDOW data. Attempt to duplicate the condition that causes DTC to be set. If conditions can be duplicated GOOD TRIP counter will change to one or more. If GOOD TRIP counter changes to one or more and no new DTCs exist, repair was complete. If GOOD TRIP counter changes to zero, this indicates that DTC has reset and repair is not complete. If OBD-II monitor failed or repaired DTC has reset or any DTCs exist, repair is not complete.
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Tuesday, February 3rd, 2009 AT 2:10 PM

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