Are you running fuel Additives? To much additive is not good New fuel runs much leaner now days so when you add more to tank motor builds more heat.
ECM could be overheating
Fuel additives??????
Stop using fuel stabilizer of any type
ECM mounted to riser??? If so make a insulator from a piece of marine grade plastic min 3/4" thick reroute air intake hose to blow cool air on ECM
This took care of my problem on my 2003 350MPI