This happens in all gears. Lets say if i'm in second gear doing about 3500rpm or so and let off to slow down and press on the loud pedal to resume speed, i'll get a small pop thru my exhaust. Just 1 pop. it sounds like the right side...hard to tell./ if i sit and just rev it i get no pop. i have roush axel backs for over a year and never had this before. car runs strong with no problems or tunes or TK. any ideas!