Ran through and read the stickies but still have trouble finding the solution.
Just got a NT11, Shoots smooth for a while... Then will start shuttering and not shooting and either break paint or be fine a minute later. It seems to be only when I ramp, and it doesn't happen everytime. Sounds like maybe the bolt is coming unscrewed as well? So I tightened it pretty tight and it did the same thing.
Well, I realized there was a crack in the eye pipe, so I purchased a dm9 eye pipe (I heard the shortened dm9 version was better) and used it, and it will still shutter and not ramp after I lay on it for a bit.
I just realized I haven't changed the battery in a while, but it isn't that old...