I second that you should check out the fuel pump. Grab a quart jar for the flow test and a fuel pump pressure gauge for pressure test and maybe a helper to turn on/off the key.

Crack and easy to get to fuel line ans just follow standard fuel pump testing procedures. specs will be in the book.

For what it's worth you did exactly what I would've done, check/change out the easy stuff first like the fuel/air filters and then move on to the more expensive/harder stuff.