Originally Posted by
mxatunerjg
I'd agree if it weren't for the testing I've done when I've encountered this issue. Except I have cleared adaptives, started the car with a wideband connected. Watched the vehicle o2 sensor data and a wideband both read correct, then as soon as closed loop begins the trims on the left bank only rise to 30% and the wideband go to 10.0 AFR and the vehicle o2 read max rich. Yet the right bank was dead on 0 trim and both the wideband and vehicle sensor for that bank be right on. I've even gone as far as running an extension harness on the left and right primary sensors and physically putting the sensors in the opposite banks. The same result, bank 1 would rise to max trim and bank 2 would stay at or near 0 trim in the computer. This all can happen to a car that has been running and driving for days, then all of the sudden one bank trims wildly rich or lean. I've unhooked the battery and fixed it, and I've replaced PCM's and fixed it, all with no change at all to the tune.