I just had to write this. My '03 Ultra was notorious for deceleration popping. Every time I would back off on the throttle, especially while going down a hill, it would start "popping". It was pretty bad. I mentioned it on this forum and it was suggested that their might be air getting in the exhaust ( Glider ). Come to find out he was correct, the rear head exhaust pipe was split. I have since fixed that but still there was a decell popping, not as bad, but it still persisted. It was also suggested that a TFI would cure that. Well I finally had one installed last week and there is absolutely no more popping. I go down that same hill and back off the throttle and the RPM's, just to see if I can bring on a pop and nothing. No noise, no popping. Can't tell ya how happy I am now! :s