[Tony Curcio]

I've been watching this for a while, scratchin my head. Here's my guess:

Water in the fuel would start and idle fine, and it would struggle to rev up. I see you drained the fuel and replaced it in October 2011, but does the fuel cell have foam in it? If so, moisture could be retained in there, which would blend with new fuel instantly.

You mentioned that you " ..pulled the plugs a number of times and I don't see anything that screams out as being an offending cylinder". Does this mean you tried pulling the plug wires off at the cap one at a time, with the engine running, to listen for one that doesn't cause the engine to drop off?