Wow, start by checking the rpm with a hand held tach your 6v92 should be 2100 to 2250 no load then check the fuel pressure should be 55 to 70 lbs at full throttle ? does your engine have a fuel modulator sounds like you are not getting full fuel position at the injectors. You really cannot tell if the engine is at full throttle by checking the linkage on the governor housing,the rpm check is a good place to start