2004 vmax 175 quitting problem

[Gregg m]

This started last year and I took it to a boat shop to be checked on their co.puter. you are running along at 40 or 50 and the motor will shut off for 4 or 5 seconds then go back to the same running speed for 4 o5 seconds then repeat.. every time it does this u loose some speed and eventually get to slow. Then it eventually went into limp in mode and wouldn't go over 5.ph. the boat shop said that the error was an injector error. They checked all the injectors and found no problems, then they cleared the error and it was fine the rest of the year. The first of June on the river this year no problems running at 55. The end of June running at 35 the problem came back. Both times this happened it was hot out so I think it is something breaking down due to 80+ temperature. I changed the spark plugs, fuel filters etc and gave it a good service. I am wondering if the cause might be the injector relay or something else the can shut down the entire system then restart back where it was. It's not just dropping a cylinder it's stopping everything. Maybe total fuel shut-off and restart, but why isn't that shutting down the engine forcing a key restart.. any ideas I don't want to start replacing things willy-nilly until I finally find it.