POSSIBILITIES ARE NUMEROUS. As a tech when faced with intermittent problems we use a light bulbs tieD to half the circuit (POWER OR GROUND). if a ground is suspect clean and reattach then put a bulb on that ground and run your own power wire. if the bulb goes on and off.....same can be done on the power side.

ignition switch or bad relay is also potentially a problem.

one theorizes what it might be and then eliminate possibilities one at a time. I've also had to borrow another control module and using it instead of the original see if the little box is the culprit.

GOOD LUCK

RETIRED ASE MASTER TECH.

Follow the lines to your battery and make sure nothings ripped open or loose. If you see anything that could be ripped or split open to the cables use electrical tape to seal it. If you can't find anything it could be a blown fuse or short circuit somewhere in your wireing. I'd try searching the web more to try and debunk it hope I helped good luck

I would guess, and mind you this is an educated guess, you have a loose main ground. Check the connection of the negative battery cable at the battery and at the ground point. Look for a grounding strap and make you it has a good connection.

Shellfish on the bodywork and decided fishy odor

tells me it needs to be towed back under the pier.

Plugged fuel filter and or low fuel pressure.

Sounds like your oscillation adjustment screw is loose.

Dirty battery terminals. Remove them, clean them up with a terminal cleaner, reattach, problem solved