Ok, I have had it happen a couple times and Im not sure why. Especially those who just are interested in SD tunng make sure your map sensor scaling is correct in the appropriate tables IE boost control, SD settings. Ive had mine revert back to another settng at one time or another, but just as a reminder, if youre having trouble with fueling!

 

Funny, I had this happen to me a while back. Went to flash a previous map back after playing with some of the ISCV tables and that sensor scaling got out of whack. I assumed I some how changed it, although I hadnt been in any of those tables at the time, much less playing with sensor scalings. Interesting.