LOL...welcome to the boating world.
The computer on a boat uses MEFI, does not work with OBD (automotive) type scanners. kills me, as I own 2 VERY good scanners and can't use them on the boat. 3 hours away? may want to try fixing the easy stuff first. Again, check for corrosion and grounding problems. If your water temp sensor is working at all, you can write that one off. top right side sounds like MAP sensor...can you take a picture? this IS an automotive sensor, shoud cost about 30 dollars, which is a lot cheaper than 3 hours of hauling. for your engine, 1998 camaro 5.7 parts should fit. always take the part with you to the automotive store because electronic sensors are not returnable. The fact that unplugging it and plugging it back in allows it to run the rest of the day really sounds to me like a corrosion problem. Get some contact cleaner and dielectric grease, clean EVERY sensor connector, again looking for corrosion and bad connections. make sure the previous owner grounded the stereo system straight to the battery and not to the engine block. Same with the power wires, should not be tied to starter (this would be more difficult but I ahve seen crazier). those 2 ground wires that are supposed to be on the bolt connecting the transmission to the engine really need to be there, you ahve the same engine as me, I'll look tommorrow to see where the other end is.
Jamie Warwick
Rowlett Texas
2002 Supra Launch 22