If the caps break down and leak, they generally fry the ECU. They are a cause, not a symptom. The ECU can fail with intact caps.

The fuel pump is in the tank. There is a plethora of information on removing it, as it is one of the most hated jobs for 1G owners. I doubt your issue is in there, but it wouldn't hurt to throw some penetrating oil on the sending unit studs while you're thinking about it.

As far as checking the sensor.. I'll leave you to Mr. Richardson's much more capable hands.