Seems like most 77 z owners I've talked to have this problem, and I'm looking for a solution. Under WOT to Mid throttle positions, when shifting, it backfires out the exhaust.Also, when revved in neutral, it backfires about when it hits 3500 rpm, on the way down. Otherwise it runs very strong (127 indicated) and gets 20 city, so I don't believe it's running too rich..Fuel level has no bearing on this little FI buggaboo. Any ideas or suggestions, please let me know. Thanks in advance!