Try replacing the fuel accumulator.

It's a cylindrical container that lives near the fuel tank under the rear of the car. It's designed to hold fuel pressure in the fuel lines to prevent vapor lock (ex: gas gets hot, turns to vapor, engine can't spray it, car has difficulty starting).

They do tend to go bad and if yours hasn't been replaced recently, I would check there first.

It's nothing more than a spring pushing against a valve. The fuel pump overcomes the spring. It also serves to dampen the vibrations in the fuel system which can also damage the WUR (takes a long for this to happen).

Bought mine for $100 USD, it's very easy to replace(socket, phillips head driver, and a vice grip to close off the fuel line), just make sure you don't get gas dripping on your arm and be careful to do this repair when the fuel tank is low in case you end up cracking the fuel hose line!

__________________
-Typos courtesy of my mobile phone.