ok . the thing I would check .

First the mefi controller is batch fire what happens is cly 2,8,3,5 and 1,7,4,6 fire the injectors on two circuits . both have 12v on when the ignition is on so what happens is the negitive is grounded by the computer . I have seen where the negitive side is shorted to ground and will cause the injectors to fire full open until the engine is flooded .

Second if in ruff water the engine can hits the rev limiter several times the engine will ether shut down or go into a limp mode . The delphi mefi controller have safety controls for example low oil , low voltage less than 10v can cause a lot of problems seen most of the time under high engine load . Over heating can make the engine go in to a limp mode .

Third , secondary ignition , spark plugs, plug wire , and cap and rotor , also seen most under a heavy load . seen most between 3000 and 45 hundred rpms

I hope this helps if you are in southern ca. we tune and diag a lot of mefi controller issues

chris