Corphish

I I change my fuel filter and ended up breaking my super rusty gas tank as I carefully toolkit off my 83 rx7. I started my car once I rigged up a makeshift demo gas tank using a boat gas tank due to being kicked out of my house. I started it up and ran strong all weekend until today. It just stalled and died on me while I was driving. I was stuck on the side of the road for a good 3 or so hours in the cold. My next thought would be fuel pump since everything else has been replaced that has to do with gas other than the carb. Please give me as much information as you can about how to find it, test it, and any information someone can give me about making my car run. Any help is appreciated.