So, while fishing a few weeks ago the motor died when we came off plane a back to idle. Gave nor horns or indications it was sick while running or through a no-wake zone a few minutes before. It would fire we we cranked and just stumble for a second and die. Tow back to ramp. Went out next day to fish on TM and tried it for kicks and it would stumble a bit longer but die and won't run. The next day, went out on the TM again and tried it again. Was able to get it running long enough to go about half a mile but died again. At this point I stopped trying due to fear of doing further damage.
Took it to a local, well respected shop and they are thus far stumped. They can get it run if the squirt carb cleaner in it and it will show good pressure on the compressor (~90psi) and with the fuel system (~80psi). The opened up the vapor canister and it was clean but they replaced the fuel filter and my old grey fuel lines with new stuff with no change. They had a working engine on hand so they swapped out its vapor canister and both fuel pumps with no luck. They also swapped out the computers. My was not showing any 'hard codes'. It didn't help my motor and the other motor ran fine on my computer.
At this point they are somewhat at a loss. Perhaps it is a sensor of some sort or a diaphragm that's not holding pressure in the fuel rail? They are continuing to work on it but I wanted to see if anyone here might have some similar experience that will shed light on this.
Also, this is the same engine from the following thread where I seem to have a bad alternator: http://www.bbcboards.net/showthread.php?t=802998