2016 G21 H6 - DTC 1087 Fuel Pressure Lower than normal warning

[IceyTys]

Hoping someone could point me in the right diagnosis direction. Boat started suddenly sputtering, then died on the water. We kept getting this DTC 1087 Fuel pressure lower than expected message. I replaced the fuel filter which looked somewhat dirty and replace the fuel/water separator canister. Put it all back together and I am still getting the same message about 30 seconds after restart. Wondering what items to check next.

This is for 2016 G21 w/ H6 Engine.

Thanks in advance.