Hi! I'm new here!

I recently bought an '83 DT500 Pace Car, and plan to restore it. That is, if I can keep it running. I drove it for one day. The gas gauge got to about 1/8 of a tank, I put a fresh premium in it, and that's when the trouble started. It starts hard, idles as if the cam has been messed with, lopes along for a little while, then quits. I took it to my mechanic, he put some cleaner in the tank, revved it for a few minutes, and declared it fixed. I got a little way down the road, and it quit. He then replaced the distributor, let it run for about an hour in the lot, then we drove it around for a little while. It wasn't perfect, but it didn't stall. It was down to about 1/8 tank, I put half a tank of premium in it, and, lo and behold, same problem. Stranded again. Called my mechanic, and he said it was debris in the fuel tank, just run it.

Before I got the car, it had been sitting for a looooong time. Minimum 6 months, though I suspect it was a lot longer. I asked the previous owner how long the fuel had been in the tank, etc. He said "not long", and that he started it up every few days.

I am absolutely in love with this car, and I refuse to give up on it. I've tried to narrow down the problem on my own (mainly by lurking on these boards), but I know when to admit defeat. Any insight would be greatly appreciated, thanks.