I've been having low fuel pressure issues for about 3-4 months now and finally it got so low the truck died. It will still start and run but pressure is really low (2-4 psi). I have a Walbro pump with 2 mic filtration set up. I've replaced the filters twice and the pump twice. Dropped the tank and inspected the pick up tube which looked fine. Thinking now the voltage to my pump may be failing. I replaced my stock batteries with Interstates about 2 years ago and ever since I've had to clean the terminals about every 2-3 months because of corrosion. They sweat a little as well. How do I check the voltage the pump is seeing and what do I need to do it?

 

There is a relay. Fried contactors inside the relay can reduce the voltage or available amperage to the pump. Replace the relay and see if your problem goes away.

 

Is this something that can take some time to fail, or would it go out all at once?