I have a 2008 Ultra Classic. At the 1000 mile service I ordered and had installed the Supertrapp slip ons (dealer said they were the same as the SE slip ons), SE high flow air, and the SE tuner...the bike sounded awesome...a little more throaty at cruise, but not too loud, and it would bark when you got on the throttle...just what I wanted. And the power and performance was noticeable...I was stoked...until two weeks after getting the upgrade I have been experiencing the same thing you described...and it does it intermittently...no power or torque when climbing hills (when it had this for the first two weeks after the upgrade)...the exhaust doesn't have that pop either when it is doing this...it sounds flat...it feels as though it is running on one cylinder or that the rear cylinder is dropping out...the bike experiences a "lurching" vibration when accelerating when it is acting up like this. I feel that it is the rear cylinder because it doesn't get hot like it did for the first two weeks. I've had it back to the dealer 4 times and they say nothing is wrong. I turned off the engine management system, but it didn't make a difference. I'm so disappointed now, wishing that I hadn't done the upgrade. 09StreetGlide, you said it was the coil connections. Can you give any more detail? I want to try to get this fixed. I was told to check the battery connections as well. If anyone can help, I'd be in your debt.