I have been fighting this issue for a few weeks now. the fuel trims will be off as much as +- 15% at idle and tapper to near 0 as rpm goes up. I checked for vacuum leaks and dont find any and same issue. A few more minutes into the log fuel trims are back to normal. I have been using this MAF curve for a few months now and have had zero issues until recently and verified that by going back and checking old logs. Car is 12 gt with JLT2 CAI, no cats with pypes axle back. Im looking for someone who may have experienced similar issues or have any ideas at what to look at. Ill attach log that shows trims off at beginning of log and a few throttle blips and trims come back to normal. I have searched quite a bit but not have not found anything that is the obvious answer.