Hey everyone....this is my virgin post. Lots of reading and research and now decided to join. Great site!
I've been chasing a P0305 (cyl 5 misfire, according to O'Rielly's scanner) on my 00 LS 3.0 5spd manual (167K) for months.
From the research I've done, I believe I have covered most common issues, eliminating them from being suspect.
The missing is very irratic, random and has no pattern at all. It will do it hot or cold. Sometimes I have a nonconsistant miss at idle, sometimes not. Cruising at temp, I will sometimes experience what seems to be a complete single cylinder loss and is cleared by depressing the clutch and revving a few times. It always returns to some degree but usually sets the code and at times, the CEL flashes. (When it flashes, I get out of the throttle right away, depress the clutch, cycle the ignition, release the clutch and then the condition seems to improve and the flashing CEL stops.
Other times, I get inconsistent jerking or bucking, almost like I've lost spark, fuel or air to all cylinders. It's a few abrubt bucks and then fine.
When the idling issues occur, sometimes I have a very strong sulfer smell, which I know is the cat to which I believe is a lean issue. However, the only code that ever sets is P0305. I don't ever have a fuel soaked plug but to my read of it, I'd say it is a bit too cream colored, indicating a lean problem. It also seems to sometimes clear when I shut the car off and restart it imediately.
I've got terrible fuel economy right now and I feel that the car lacks throttle response until the tach reaches 4K and then it's like the sensation of when reeds open on a two stroke.
Since chasing the issue, I''ve done the following:
1. New VC gaskets due to oil intrusion.
2. New COPs and boots on all 6 cylinders (also moved them around, no result)
3. New MAF - housing had a crack (noticable improvement, but no resolution)
4. New upper intake gaskets
5. New Cam Sensor
6. New OEM recommended plugs
8. Fuel filter
9. Air filter
10. Seafoam fuel treatments
11. Verified no PCV vacuum leaks (engine was replaced and PCV valve location is now at the back of engine, not center of intake)
12. Sprayed entire intake & EGR areas with brake clean while running, no idle change
13. Swapped IAC with known good
14. both cats replaced (about 1 yr ago due to breakdown)
15. Both mufflers replaced due to cat debris & potential plugging
16. Verified all air intake junctions are tight and not leaking
17. Compression at 120ish, same as most other cylinders
18. With the upper intake off, I observed the injector spray. It is nice and conicle with no dripping or leaking.
19. Traced #5 wires to COL back into harness for visual inspection of damage/short.
20. Newer Alternator and New battery
I've just ordered the IMTV o-rings that will be in tomorrow that I am going to try but am not optimistic because I do not have the typical two codes that usually call out the vacuum leak, and I do not have any oil residue or vacuum leak hissing noises. However, my theory on this still being a possibility is the drivers side cylinders look to be primary subject to the long runners (top), which is default for the IMTV under lessor load. When I get it past 4K, my issue clears, at the same time the IMTV is likely switching to the short runners. From what I've read, people still have IMTV leak issues, even if a vacuum leak is not heard nor detected by a spray test.
If the orings don't resolve the issue, I would also consider a partially plugged injector/injector screen and may throw a new set of injectors at it. With the miles on it and if one is a problem, I don't want to tear it down in a week to replace another.
I've thought about fuel pressure, but again, would think I would get more codes than cyl 5 misfire. I'm not beyond checking it though. Also wondered if I have an exhaust restriction in the left side center section between cat and muffler but again, would think I would see more codes than just cyl 5.
I also suppose I could have an ECM grounding issue but seems like it would be a pretty rare exception. Possible I guess. Other than that, I could also locate the pins on the PCM from #5 COP and Injector and do a resistance check to see if I have a wiring problem, but again, seems uncommon and unlikely.
I doubt there would be a relationship here, but figured I should mention it just in case...I also have an occasional ABS light with codes for no signal from left or right front sensors. (both hubs and sensors were replaced about a year ago with Timkin brand replacements due to bearing noise, yet the codes still set periodically.) Could the misfire problem and the ABS codes be a common result of a failing PCM? Or did I simply install some POS hubs & sensors and need to replace them again?
I've begun to wonder if the scanner is setting a generic code misfire code and is selecting P0305 to display but cannot find any information to support that possibility. I don't know....but have never been closer to thowing the towel in on a car issue than this. Love the car, but what a PITA this has been.
What are thoughts? Can someone provide specific details on what to test next or what I may be overlooking? If injector/COP wiring test to the PCM is suggested, could someone please provide the PCM connector number and related pin numbers for #5 coil and injector?
Thanks Much!
I've been chasing a P0305 (cyl 5 misfire, according to O'Rielly's scanner) on my 00 LS 3.0 5spd manual (167K) for months.
From the research I've done, I believe I have covered most common issues, eliminating them from being suspect.
The missing is very irratic, random and has no pattern at all. It will do it hot or cold. Sometimes I have a nonconsistant miss at idle, sometimes not. Cruising at temp, I will sometimes experience what seems to be a complete single cylinder loss and is cleared by depressing the clutch and revving a few times. It always returns to some degree but usually sets the code and at times, the CEL flashes. (When it flashes, I get out of the throttle right away, depress the clutch, cycle the ignition, release the clutch and then the condition seems to improve and the flashing CEL stops.
Other times, I get inconsistent jerking or bucking, almost like I've lost spark, fuel or air to all cylinders. It's a few abrubt bucks and then fine.
When the idling issues occur, sometimes I have a very strong sulfer smell, which I know is the cat to which I believe is a lean issue. However, the only code that ever sets is P0305. I don't ever have a fuel soaked plug but to my read of it, I'd say it is a bit too cream colored, indicating a lean problem. It also seems to sometimes clear when I shut the car off and restart it imediately.
I've got terrible fuel economy right now and I feel that the car lacks throttle response until the tach reaches 4K and then it's like the sensation of when reeds open on a two stroke.
Since chasing the issue, I''ve done the following:
1. New VC gaskets due to oil intrusion.
2. New COPs and boots on all 6 cylinders (also moved them around, no result)
3. New MAF - housing had a crack (noticable improvement, but no resolution)
4. New upper intake gaskets
5. New Cam Sensor
6. New OEM recommended plugs
8. Fuel filter
9. Air filter
10. Seafoam fuel treatments
11. Verified no PCV vacuum leaks (engine was replaced and PCV valve location is now at the back of engine, not center of intake)
12. Sprayed entire intake & EGR areas with brake clean while running, no idle change
13. Swapped IAC with known good
14. both cats replaced (about 1 yr ago due to breakdown)
15. Both mufflers replaced due to cat debris & potential plugging
16. Verified all air intake junctions are tight and not leaking
17. Compression at 120ish, same as most other cylinders
18. With the upper intake off, I observed the injector spray. It is nice and conicle with no dripping or leaking.
19. Traced #5 wires to COL back into harness for visual inspection of damage/short.
20. Newer Alternator and New battery
I've just ordered the IMTV o-rings that will be in tomorrow that I am going to try but am not optimistic because I do not have the typical two codes that usually call out the vacuum leak, and I do not have any oil residue or vacuum leak hissing noises. However, my theory on this still being a possibility is the drivers side cylinders look to be primary subject to the long runners (top), which is default for the IMTV under lessor load. When I get it past 4K, my issue clears, at the same time the IMTV is likely switching to the short runners. From what I've read, people still have IMTV leak issues, even if a vacuum leak is not heard nor detected by a spray test.
If the orings don't resolve the issue, I would also consider a partially plugged injector/injector screen and may throw a new set of injectors at it. With the miles on it and if one is a problem, I don't want to tear it down in a week to replace another.
I've thought about fuel pressure, but again, would think I would get more codes than cyl 5 misfire. I'm not beyond checking it though. Also wondered if I have an exhaust restriction in the left side center section between cat and muffler but again, would think I would see more codes than just cyl 5.
I also suppose I could have an ECM grounding issue but seems like it would be a pretty rare exception. Possible I guess. Other than that, I could also locate the pins on the PCM from #5 COP and Injector and do a resistance check to see if I have a wiring problem, but again, seems uncommon and unlikely.
I doubt there would be a relationship here, but figured I should mention it just in case...I also have an occasional ABS light with codes for no signal from left or right front sensors. (both hubs and sensors were replaced about a year ago with Timkin brand replacements due to bearing noise, yet the codes still set periodically.) Could the misfire problem and the ABS codes be a common result of a failing PCM? Or did I simply install some POS hubs & sensors and need to replace them again?
I've begun to wonder if the scanner is setting a generic code misfire code and is selecting P0305 to display but cannot find any information to support that possibility. I don't know....but have never been closer to thowing the towel in on a car issue than this. Love the car, but what a PITA this has been.
What are thoughts? Can someone provide specific details on what to test next or what I may be overlooking? If injector/COP wiring test to the PCM is suggested, could someone please provide the PCM connector number and related pin numbers for #5 coil and injector?
Thanks Much!
