Throttle Position Sensor Adjustment ?
 

Hope all is well with everyone;
I have a Built 502 Mag=509 with m3 Procharger, 27 Baja... I have noticed a loss of power and decreased rpms and top speed. My wide open Throttle reading on a mercruiser scan tool is reading only 79%. I checked cable adjustment and it is correct. Could the TPS vibrate loose? And ls it adjustable? Any accurate info is greatly appreciated.

Did anyone reprogram the ecm? There is a throttle angle calculation table in the ecm that may not be set for your engine. If not, then you can either zero the tps at idle with the scan tool or use a volt meter and set it to .5 volts at idle. It is possible that it moved, but not likely that much.
Eddie

I have had many problems on cars with efi. make sure you are getting appropriate reference voltage to all sensors that use it. i have had many a/c cycling switches and ep sensors on trucks drag down reference voltage and make things like that happen.

and do what eddie says. he knows his stuff.

Thanks for the info, Precision Marine programed the ecm, I am planning to call them in the am to see if they have a record of the settings. The motor is all new.