So I was talking with a workmate and he was having problems with power loss under load.
I suggested the usual......change your spark plugs, wires and fuel filter.
He changed his plugs & wires and the problem was not quite resolved.
So last weekend on my home in my T/A I started experiencing similar symptons. It would pull up to 3500 rpm then stutter like it hit a rev limiter.
I changed my plugs and that didn'd resolve it so i then changed my fuel filter and magic, the power was restored back to wheel spinning glory.
Tonight my buddy is changing his fuel filter. :P