Hmmmm, do you have (or can you borrow) a multimeter that measure current - AMPS? Also it should be able to handle at least 10 to 20 amps

If yes, check the fuel pump current draw, to do this get a flashlight and some foam to kneel on, look in the passenger side footwell, look up into the front, top, right corner, move the upper panel at the corner to get your fingers in there. You will see or feel a fairly heavy guage wire with a connector which joins the wires.

There is not much slack in the wire so be carefull that you grasp the whole connector and work it out from behind the panel.Once you get it out understand that the wire from the connector that goes toward the front of the car goes to the MAS control unit (pin 2 i think). MAS unit controls (powers) the fuel pumps and the AC compressor as main functions.

The wire from the connector that goes toward the rear of the car goes to a dual connector under the rear seat, then directly to the fuel pumps.

You may need a helper for the following....make sure the meter is set to measure AMPS and check that the leeds are in place properly, then hold one lead from the meter firmly into the female connector and clamp or firmly hold the other lead onto the male connector. Have someone start the engine and read the meter...it should read between 4 and 8 amps with the engine running.

Do this test first with the engine warmed up, read the meter and write down the results over a period of 20 seconds.

Test again with a cold engine and write this down. If both tests give you the same reading, consider replacing the one-way check valve at the fuel pump.

Good luck,
Acky