I used the scanner today to diagnose a poor running condition on a 2008 1500 Sierra denali with boost. Its been previously tuned and had a few mis fires as well as fueling was a bit inconsistent. For some reason I couldn't get it to display stft and ltft. Wondering if possibly its in open loop from previous calibration and is this is the symptom of such not being able to see trims or if I didn't have the vcm pids set up right.
