Question:
On this vehicle, do you feel the misfire was present from startup and got more severe with time to set both the FF and FR or the misfire occured when the FF and FR were set?
Answer
I believe #6 fuel injector was stuck closed upon startup and that the problem did not worsen over time, but that the onboard diagnostics did not flag it until later. One possibility comes to mind; misfire diagnostics will be disabled if the fuel level is below 15%. The misfire that set the MIL happened 21 miles previously and the fuel gauge was now past full. Perhaps the diagnostic was disabled due to the fuel level and as the vehicle was either driven on a grade or the fuel level changed enough while sloshing that the diagnostic was run.
Question:
Did we have any O2 heater codes?
Nope, no O2 heater codes were set.
In California, these injectors are now warranted for 10 years or 100k miles. The dealers are not overly excited since GM has also CUT the warranty pay and REMOVED all diagnostic pay for their diagnosis and removal. Real nice people….