por max 225 problem

[jay j]

1998 pro maxx 225ss. cranks and idles fine. off idle speed
at about 1500 to 4500 rpm motor does not respond, sort of like running out of fuel. i can punch it and i have a major bog but motor comes right back and revs to 8500rpm. limiter
is out and it has a 16amp flywheel. i also have a 200 pmss
and had it on the same midsecton. it ran flawless. i have disconnected the 2 tan wires from the temp sensor on the head that goes to the air map and tps. problem goes away but
the motor is now way to rich and will not idle. i put a 470
ohm resistor in plcae of the sensor,motor is now leaner and harder to start, but still has the problem. i took the airmap sensor and tps off my 200 and installed it on the 225
it is the same and the problem is still there. nobody seems
to know what it can be. merc hi-performance said it was the mapp sensor. wrong. sean at rapair has helped so far but
now it seems that the ecu is the culprit. i have a friend that has the same year and model motor, but he is afraid of
damaging his unit by letting me try it on mine. can anybody
help?