Can't get 2002 to start.

I inherited a 1970 2002 from my dad a few months ago. It had been sitting in his barn for about 12 years. I took the gas out of the tank and had the thing boiled out and re-installed it. The car took about 15 minutes to get fuel running through it (put on a new filter as well) but it finally started up. It ran for 2 weeks with no problem. Then, one day it just decided to not run.

My dad recommended that I replace the fuel pump. So we did that and it started running just fine again. Another week goes by and the thing dies again.

I have no idea what else to do. When I pour gas into the carbeurator it'll start up briefly but we can't get it to stay running for more than a minute. I love the car, but it's really frustrating me because I have no idea what else it could possibly be.

I'm up for any ideas you got!