Confirm diagnosis

I have a 1999 Jaguar XK8 convertible with about 90,000 miles. I was driving it in the foot hills of west georgia and it didn't seem to have a lot of its power, thought it might be time to replace plugs and tune up. Parked the car and it wouldn't run after a couple of hours. It ran very rough and I got the feeling it was starved for fuel. Checked the schrader valve on the fuel rail, and it had some pressure at first then it went to none after some time. Checked the fuel pump fuse and the relay, it clicks as if its picking up. 99% sure its the fuel pump, but I was wondering what you thought, and what wires to check to see if it is getting power.