Consistently negative LTFT

[seppstefano]

I guess much more than 10%. My Scangauge returned great results after each ECU reset. I might also install a switch inside to physically power the ECU off and let her start everytime from scratch...

[topcat]

Hang on there. Negative LTFT means that the ECU is adding less fuel than its base map would expect. Surely that's a good thing... right?

In a car which has learnt a negative LTFT, resetting the ECU (back to its base map) is going to mean too much fuel gets added in until the ECU re-learns.

I guess it depends whether the error is in the final O2 meter or some place before that. Frames of reference and all that.