I think you'd be better posting this in the engineering and tech. area.
As # 2 seems dramatically different to the other cylinders, i'd be investigating this further.
I'd make a wild guess, based on the given info. that worn camshaft lobe (s) is/ are preventing this cylinder from "breathing properly....in fact, i'd say inlet!
If the engine and prop are mechanically balanced, then it must be down to differences in power-output (or friction-losses on the other 3 strokes).....Now! there's a thought!...has #2 had a partial-siezure?
it would not only give reduced output, but the tight piston would have a lot higher drag!.
I'm NOT an aircraft mechanic, the info is worth what you paid for it!
