Fuel sensor or fuel injection problem

Boat: Malibu wakesetter VLX with '03 Indmar Monsoon 335 EFI engine

Late last season my boat started to cut out while wakeboarding and loaded. I wouldn't go past 11mph and would sputter if I pushed the throttle forward. I could turn off the boat and bring it up to 25mph for about 3-4 minutes then it would start cutting out and go back down to 11mph. The 1st time I took it to the shop they cleaned a fuel strainer that had some sand in it they said. That fixed it for about a month. I took it back and they replaced the fuel filter (didn't have the part my previous visit or would've done it then) and then the season was over, after about 1 month's use this year the same problem is occurring. Does anyone have any troubleshooting ideas, possible candidates, or suggestions as to what might fix or temporarily remedy the situation? The boat only has about 350 hours on it, I'm the original owner, only been in lake water and it's been taken care of pretty well w/o any big problems.

Likely the fuel line is gummy from alcohol in the gasoline. Replace the fuel lines and this will likely take care of the problem.