Doc99SS
10-23-2005, 06:27 PM
In coming home two weeks ago (200 mile trip),, the SES light come on and the engine started to run a little rough.
I limped the car home and check for DTC codes. I had multiple misfires and mainly on #3. The misfire history on #3 was in the many thousands.
I pulled some plugs and found that they were very sootie black. Pull one O2 and it was in bad shape, also. The LFTFs were +25%. I judged that the O2 were reading lean when it really was not. I had turned the PCM to -5% LTFT in most FTCs. So I figured that if I installed new front O2 sensors and all new plugs, clear the DTC codes, the engine would be back all good with no misfires.
But that did not happen, I still had a noticable miss, as well as, ATAP telling me random misfires on #3.
So I swapped #1 coil with #3, cleared codes, no change, still have misfire #3.
Now, I swapped #1 plug wire for #3 plug wire, cleared codes, still #3 misfires.
So whats going on??? Can the PCM identify the wrong cylinder? maybe its a misfire on #6 for example.
In addition, some searching turned up a CKP Learn procedure, what is this thing?
I limped the car home and check for DTC codes. I had multiple misfires and mainly on #3. The misfire history on #3 was in the many thousands.
I pulled some plugs and found that they were very sootie black. Pull one O2 and it was in bad shape, also. The LFTFs were +25%. I judged that the O2 were reading lean when it really was not. I had turned the PCM to -5% LTFT in most FTCs. So I figured that if I installed new front O2 sensors and all new plugs, clear the DTC codes, the engine would be back all good with no misfires.
But that did not happen, I still had a noticable miss, as well as, ATAP telling me random misfires on #3.
So I swapped #1 coil with #3, cleared codes, no change, still have misfire #3.
Now, I swapped #1 plug wire for #3 plug wire, cleared codes, still #3 misfires.
So whats going on??? Can the PCM identify the wrong cylinder? maybe its a misfire on #6 for example.
In addition, some searching turned up a CKP Learn procedure, what is this thing?