kbwford
New Member
2005 Ford Expedition with 5.4 Triton 3V
Unfortunately this will be a long story as it has been on-going for some time. I have run out of ideas and am hoping somebody has encountered this problem.
Truck has 138,000 miles. Oil was changed regularly using Motorcraft Semi-synthetic 5W-20. Compression is good.
The truck started running rough a few months ago (no code) so I changed the spark plugs which I knew were lng overdue. I used high end autolite plugs. This corrected the rough condition.
A month later, the rough condition reappeared and this time set a P0304 code. (misfire cyl 4) I swapped the #4 and #1 coil packs to determine if the problem moved to #1. It did not. The code came back and was again P0304. Given I knew it wasn’t a coil pack and the fuel injectors had almost 140K on them, I replaced all 8 injectors. Note that this procedure required disconnecting and removing the PCM to gain access.
Started the truck up and noticed it was still missing. Once the check engine light came on, the codes were (P0303, P0307 & P0300). Random misfire and misfires on 3 & 7. Now I’m confused, the miss has moved from cylinder 4 where it coded consistently for a few weeks. What else is there? I decided perhaps one or more coil packs were marginal so I replaced all 8 of them and cleared the codes. Note that this procedure required disconnecting and removing the PCM to gain access. The truck still had a miss.
The check engine light came on a day later. P0303 – misfire on cylinder 3. So again, the problem has migrated from cylinder 4 to cylinder 3. Why? Replacing the plugs, injectors and coil packs should not have moved the miss. It may have fixed it, but not moved it.
Now I’m perplexed. Used a quality scanner to check O2 sensors and cam sensors. All appeared to be good. For the kicks, I swapped the position of the bank 1 and bank 2 cam sensors. Truck coded again with P0303.
OK, why did it move to #3? Did I somehow put a bad part in #3? Listening to the injector with a long PVC pipe, I could hear that the #3 injector was not firing. Brand new injector, why not firing? I don’t have a noid light but a test light showed steady voltage at the injector wires. I put a second new injector in #3. Started the truck and listened again, injector 3 still not firing. All other injectors sounded fine and were clearly firing.
A day later the check engine light came on…codes were: P0174 – Bank 2 too lean, P0207 – injector 7 circuit malfunction, P0300 – random misfire, P0305/P0307 – misfire cyl #5 & #7. OK, big change here….why? All that was done was to change #3 injector. Note that this procedure required disconnecting and removing the PCM to gain access. Once again, the problem has moved, this time from #3 to #5 & #7.
For kicks, I replaced the bank 2 cam sensor since I had the too lean condition and a miss on 5 and 7 both of which are on bank 2. I cleared the codes. Miss still there. A day later a code set and it was P0305.
I have cleared the codes numerous times since and it always resets now with P0305. Note I have not disconnected the PCM during this period where the code is consistent at P0305.
Early on during this long diagnostic procedure I have inspected and cleaned with electrical cleaning solvent the connectors where the harness mates with the PCM.
I am baffled at this point and do not know what to test next. Any help would be GREATLY APPRECIATED.
Unfortunately this will be a long story as it has been on-going for some time. I have run out of ideas and am hoping somebody has encountered this problem.
Truck has 138,000 miles. Oil was changed regularly using Motorcraft Semi-synthetic 5W-20. Compression is good.
The truck started running rough a few months ago (no code) so I changed the spark plugs which I knew were lng overdue. I used high end autolite plugs. This corrected the rough condition.
A month later, the rough condition reappeared and this time set a P0304 code. (misfire cyl 4) I swapped the #4 and #1 coil packs to determine if the problem moved to #1. It did not. The code came back and was again P0304. Given I knew it wasn’t a coil pack and the fuel injectors had almost 140K on them, I replaced all 8 injectors. Note that this procedure required disconnecting and removing the PCM to gain access.
Started the truck up and noticed it was still missing. Once the check engine light came on, the codes were (P0303, P0307 & P0300). Random misfire and misfires on 3 & 7. Now I’m confused, the miss has moved from cylinder 4 where it coded consistently for a few weeks. What else is there? I decided perhaps one or more coil packs were marginal so I replaced all 8 of them and cleared the codes. Note that this procedure required disconnecting and removing the PCM to gain access. The truck still had a miss.
The check engine light came on a day later. P0303 – misfire on cylinder 3. So again, the problem has migrated from cylinder 4 to cylinder 3. Why? Replacing the plugs, injectors and coil packs should not have moved the miss. It may have fixed it, but not moved it.
Now I’m perplexed. Used a quality scanner to check O2 sensors and cam sensors. All appeared to be good. For the kicks, I swapped the position of the bank 1 and bank 2 cam sensors. Truck coded again with P0303.
OK, why did it move to #3? Did I somehow put a bad part in #3? Listening to the injector with a long PVC pipe, I could hear that the #3 injector was not firing. Brand new injector, why not firing? I don’t have a noid light but a test light showed steady voltage at the injector wires. I put a second new injector in #3. Started the truck and listened again, injector 3 still not firing. All other injectors sounded fine and were clearly firing.
A day later the check engine light came on…codes were: P0174 – Bank 2 too lean, P0207 – injector 7 circuit malfunction, P0300 – random misfire, P0305/P0307 – misfire cyl #5 & #7. OK, big change here….why? All that was done was to change #3 injector. Note that this procedure required disconnecting and removing the PCM to gain access. Once again, the problem has moved, this time from #3 to #5 & #7.
For kicks, I replaced the bank 2 cam sensor since I had the too lean condition and a miss on 5 and 7 both of which are on bank 2. I cleared the codes. Miss still there. A day later a code set and it was P0305.
I have cleared the codes numerous times since and it always resets now with P0305. Note I have not disconnected the PCM during this period where the code is consistent at P0305.
Early on during this long diagnostic procedure I have inspected and cleaned with electrical cleaning solvent the connectors where the harness mates with the PCM.
I am baffled at this point and do not know what to test next. Any help would be GREATLY APPRECIATED.
