I need help with a 03 450f that is burbling, coughing and popping at around the half throttle range. WHen you are riding it as soon as you start to cut back on the throttle she starts to sputter pop and cut out. It has a Pro Circuit header pipe and Ti 4 silencer, Main jet was a 165 tried a 172 that didnt help, it has a 42 pilot, the needle was in the stock clip postion tried one higher and then one lower. I checked the accelarator pump timing and it is good. PLease help this getting to be vary annouying going up to doubles.