I recently just purchased a 2008 rxt with 62 hours on it, it hadn't run in a couple of years but I went through everything put fresh fuel in it three new spark plugs, a compression test, and rebuilt the supercharger just to be safe, I fired it up on the hose and it runs great and revs right up, I put it in the water and idled out of the no-wake zone just fine, when you run quarter throttle it seems okay as soon as you go over quarter throttle or heavier into it it feels like it's misfiring or breaking up and will only get up to about 35 mph, I put three good tested fuel injectors in it with the same problem, I'm not getting any beeps or anything although I can't read the gauges because they were broken in transit after I bought it, I'm not really sure where to start here. When I pulled it out of the water I had it on the trailer got it to half throttle where it was breaking up and unplugged the coils individually and you could hear the engine bog down further from the already misfiring it was doing, so I don't think it's a total spark issue.