1980 528i Bummer

[Xotie]

I'm sure this may have been addressed in the past, but I'll give it a try:
My daughter-in-law gifted me her old '80 528i, and I drove it from San Diego to Vegas last year - never missed a beat. While I've been waiting for the title (it's been missing), the car has not been driven at all, but started occasionally, and operated for several minutes.
Recently, it had started to stumble, die, but could be restarted after a few minutes. More recently it has become nearly impossible to start at all, but will occasionally, and only for a few minutes at most.
Fuel pump operates, and has power to it (the pump) during cranking. Fuel filter does not appear to bt clogged, and flows okay. It does start up (sometimes) and runs for 2-3 minutes, but then stumbles and dies. There is spark at plugs when cranking, but it sure seems like fuel ain't gettin' where it should.
Don't know where the FI replays are ( I have an idea, but not sure) or much else under the hood, but I'd like to get this on the road again.
Any suggestions?

[4-Door Flunky]

Hi, Xotie-
There are a couple of possibilities. The most likely one is the fuse going to the fuel pump. The fuses get old, and even though they look fine, they aren't letting all of the current go through. Also, the tab holding them in place could have lost some tension, so that sometimes there's connection, and other times there isn't.
Fuel relays also go out on these cars. I think there are two of them on yours, and they cost $30 or $40 from the dealer.
Main relay is also a possibility. I got mine from the dealer for $23.
Get some new fuses and swap those out before investing in more expensive parts. I bought mine on eBay.
Also, lots of the M20 and M30 motors were famous for having idling problems...but they always started just fine. I repeat, if you're having the classic idle problem, the car will start every time...it just won't idle right.
Good luck.
Flunky