The best way to track down this type of problem is by process of elimination. Unfortunateley, there are a lot of variables that could be causing the issue. Not to worry, it will just take some patience and following a problem elimination plan that makes sense and you keep track of.
I know it sounds dumb to keep track of stuff, but I find it helpful because I can pick back up where I left off easier when I do this.
So far, it sounds like at least the pump is working and the pump relay is at least giving the pump the prime signal. The prime signal is sent from the relay as soon as you turn the key to the ignition on position to pressurize the sytem to start the motor. Electrical parts can be tricky if they are in the process of failing. They will get hot, behave in unexpected ways that you might not expect, work intermitantly and keep working sometimes for a while before they completely fail. I mention all of this because it is too early to rule out anything completely. Also, I would hate to see you take the time and spend the money on a pump when it could be something else.
With all of that said.
The next time you start your vehicle, pull the plugs and see if they are wet. Also take note of the color. A brownish red is normal. Let me know what you find.
One step at a time and you will figure this one out.
I will check back soon and see how things are going and it will hopefully be cheaper and easier than replacing the pump.
Saturday, February 18th, 2017 AT 2:53 PM