I have a 2005FLSTCI with Screaming Eagle slip on, stage one air kit, and K&N air filter. I bought the bile last year and it was backfiring pretty bad on decell. I had a shop install a Vance & Hines Fuel Pack. The back fire has pretty much cleared up but now I have miss or studder between gear shift with low or moderate throttle. It can also happen when in a lower gear and applying gradual throttle increase. The problem only appears with low or moderate throttle. I have had it back to the shop three times to be remapped with little to no success. Any suggestions?