No idea, not a mechanic so I’m still working out the scanner I borrowed
2012 Tahoe 5.3 with Misfire on 4 ...
- Thread starter Ivanhoe
- Start date
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Did you have a CEL for a while before the Christmas Tree lit up (Stabilitrack and TC messages)?
Can you see if the scanner can provide a plot of those O2 voltages (graph style or at least running with changing values)? They should be hoping around, up and down as the engine is running, like between .75 down to .1
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Was the engine running for the second set of pics?
Long term fuel trims are way off. The PCM is reducing fuel since it thinks it's running rich.
EDIT: with both banks that far off I wouldn't rule out the MAF as a cause.
Long term fuel trims are way off. The PCM is reducing fuel since it thinks it's running rich.
EDIT: with both banks that far off I wouldn't rule out the MAF as a cause.
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Could be. Both banks showed running in open loop due to faults, I assumed it was from the random misfire code. It would be nice to see the misfire counts and understand where they are occurring (other than 4). If this scan tool can provide real time misfire count updates, it would be good to know if he still has a high random misfire condition, or if cleaning the MAF fixed that and he only has #4 to deal with.
Lookin at the screen shot he provided, the P0300 was permanent so he might not have completed the trip criteria. I don't know enough about how the ECU works to know if it will drop back into closed loop once the engine warms up, if the random misfire counts settle down, even if it hasn't met the trip criteria to clear the P0300.
