Originally Posted by
Cringer
I just turn LTFT off and keep them off. If you are ever "done" with tuning then turn them on. But the hard part of tuning, logging, revising the tune, driving, logging, etc is that you need to reset the LTFT learned values in the scanner before you drive and log each time (at least if you are making air/fuel changes). This is easy to forget and adds extra time and steps to the tuning process. And if you forget, then the potential for error starts to creep in your tune which will delay final results and have you going in circles.
The other argument is that the last LTFT value that is active will be carried forward into PE fueling. I have seen this happen on my E38. Which then throws off your attempts to calibrate PE air/fuel.