You haven't really eliminated anything yet, but the first thing I do with any old jalopy is put a new Spectra Premium gas tank in it. They are made in Canada and fit like original. That eliminates trash from the fuel pump back.
If your fuel pump has some age, why not just replace it and replace whatever filters you have in the system.
Although it sounds like a fuel problem, it could be not fuel related at all. Coils can short out when they get hot.
