I had an intermittent fuel pump on my 1995 Ford Explorer, it would only happen when starting never while running. Replaced the pump (junk yard) and everything was ok for about three weeks then it started doing it again! I connected the fuel pump directly to 12 volts on & off multiple times trying to get it to fail thinking maybe it had a bad spot in the motor, I also let it run in a bucket of fuel for an hour and switch it on & off no problem found. I did the same thing to the original pump and again no problem found they both worked perfectly! I then checked the fuel pump relay with a multi-meter for continuity and voltage, all was good. I then remembered that I had purchased a relay tester years ago but never needed to use it. So for shits and giggles I placed the relay in the tester and BAM! The tester indicated the relay was bad! Even though putting the bad relay back in the truck it worked! So I tested it again, and again the relay tester said the relay was bad. At this point I thought the tester was bad until I tested a new relay, the tester said the new relay was GOOD! Popped in the new relay and the truck has been working fine ever since, it’s been two years and running! Hope this helps you, I know I’ve learned a valuable lesson regarding relays.