I just had my car tuned on e85 and it backfires at wot in low gear (1-3) and it seems fine in 4th and 5th. Engine is a 2.3 with 272 cams and a 6266. Also has a spoiling up cop kit. With all brand new coils is this normal for an e85 tune?

 

Are you sure its a back fire & not the Rev Limiter? I never go WOT in first (way too much torque on the drivetrain for my liking)

If it is actually backfiring, I would say, No, that is not inherent to an E85 tune

 

Could it be spark blow out?

 

do you have NLTS active and perhaps are a little lazy about getting off the clutch pedal?