1990 740GL that has sat a whole lot...
Gas gauge showed it was quite low a while ago when it died on me after leaving it outdoors overnight after picking up a friend and driving their car home.
I started it up, it ran 10 seconds and died. Restarted it and it did it again. Then it cranked and sputtered but no start. I could hear the fuel pumps running, but it felt like fuel starvation. Started and it died again.

After I let it sit a few minutes, I restarted it and let it run a few minutes... it had no issues and then idled and revved in Park for 10 minutes. I drove it to a gas station and filled it up. Drove it home with no problems.

About a month later, tank still full, I started it yesterday. It did the same thing - seemed fine, then died and wouldn't restart.

While the list of possible issues is long, I think that there is a good chance there is water in the fuel. I bought a bottle of "Iso Heet" that's purely Methanol. It will mix the water into the fuel if there's only a little. But I'm not thrilled about the idea of putting it into the fuel tank and it potentially damaging something or being on the wrong track.

Do these symptoms sound like water in the fuel tank? If so, can I just drain a little and see it easily?

Cheers,
Will