p0tter7

So I have a problem here. Motor starts and shuts off 5 seconds later. Here is some details.

-fresh rebuilt 454 mag mpi gen 5. Had stroker crank, comp cam, valves replaced so on.
-new cap rotor
-New wires,
-new plugs 2 sets since I’ve started
-new ignition coil,
-stock injectors cleaner and flow matched
-also now have new injectors.
-ecu was tuned and sent back

so since rebuild I’ve had the boat in the water. The times I had it out ran good. Wasn’t going crazy since I had to mess with the tune(never got that far since problem came up, and working crazy hours). Last time I had it out on the water running good was out for few hours no problems untill my way home. I pulled up to the beach to let the dogs off and let me buddy catch up. When I pushed off and started boat again it started fine, soon as I got on it to get moving motor started to pop and wouldn’t plane out.
at that point I changed ignition coil and it didn’t help(was told it might be over heated). Double checked ignition timing. Checked all plugs they all looked fine. Replaced plugs with new set, didn’t help. Map sensor was reading(not sure if it’s correct because the ecu don’t show psi. Shows something else. (When I did the math on what the exu tells me vs psi and they are diff but I’m not sure if my math is correct. I just googled it) Everyone told me my cam is shot. Every time I started the motor since problem came about it wouldn’t start right away and take few seconds and then I’d have to play with throttle to keep it running to then idle. So at this point it’s winter time and I pulled motor. Checked the cam all checked out fine. Leak down test good, compression test good. Replaced vacuum lines. So I was stumped. Someone I talked to said my problem is the injectors. So I got new aftermarket injectors installed them. Installed motor.

Finally got time to start it. Took a min since every fuel line was dry since it was apart. Motor started and ran fine. Adjusted ignition timing (8* what I keep reading) motor tan fine for about 30 mins or so. (Wile motor was running at idle wide band on bank 1 1:3:5:7 shows lean showing 20 and bank 2 2:4:6:8 shows it’s about 15.6ish) I shut the boat off since it was late and I was happy it started no problem. Yesterday I set up to check fuel pressure and start really getting the lean condition I got everything set up, started the boat and it started but then shut off 5 seconds later. I played with the throttle started and shut off 5 seconds later. Did it few times til I said **** this thing. I’ve had enough.
things I have not changed yet. Ignition control module, map sensor, intake temp sensor. At this point thinking just get them all but I’m still stuck with what is the problem. Need help.