240M3SRT was running very lean with the new LET tune. With the colder temps outside, this may be happening to you too. Seeing 240 hitting 17 AFR last week prompted me to finally break down and buy a wideband AF gauge. Until I get it installed, I will be taking it easy on the boost. I put my car on the dyno after getting the latest LET tune and was seeing 12.9 AF but this was at 70 degree temps. I bet we all are seeing lean conditions in these cooler temps but don't know it because we all don't have widebands installed.