It sounds like it's firing with starting fluid so I'm assuming it's not getting gas. It would run on old gas if it was getting up to the injectors. Maybe not run well, but would run. I pumped 85 gallons of 5-year-old gas out of my rig and burned it in my cars without a problem (long story). It did have a stabilizer in it though.
If it worked when you parked it and doesn't now, it can't hurt to dump 5 gallons of fresh fuel into it to see if it's the steep slope causing your problem.
As others have said, you should hear a fuel pump run (prime) back at the tank when you turn on the key. It will stop after a few seconds. When you crank it (turn key to start) it senses oil pressure and will continue to run. But the key is whether you hear it at all. If you don't, that's your problem. There will also be a test port (Schrader valve) on the fuel rail somewhere. Depressing that will tell you whether you have fuel pressure to the injectors (it will also spray fuel everywhere but not a lot).
1984 Allegro M-31 (Dead Metal)