Reply To: 04 gmc envoy 5.3l

[Jeff Moore]

Replaced maf and still running lean. The one thing I have not replaced is the spark plugs. The plugs have to be shot from all the lean running it has been doing. Correct me if wrong wouldn’t the plugs not firing good cause the stft and Ltft not to read correctly, due to the un burnt fuel going past the o2 sensors.