mine also died at 86K miles. It lasted 7 years.

 

Vortec trucks run a high fuel pressure, i know with the older poppet valve CSFI injectors they would not open if the pressure was under 45psi. I had the fuel running through a gauge with shut off valve. I slowly lowered the pressure from the 60psi idle to 45 and as soon as it dipped below that it shut off.

Once the pump starts giving out and not producing enough pressure it won't run the engine. The pumps usually don't completely die, but they aren't powerful enough to feed the engine anymore.

Also, alot of the times i am worried about the preliminary sock filter they have on some pumps. I can imagine they would be easy to clog if the fuel was ever given the chance to settle and gum up. Starving the pump and burning it up.

I cut a trap door in my bed right over the pump, so a few times a year i usually remove the pump and check it. I've had so many pump failures on my 98 GMC that it was easier for me to just have a door in the bed to access. It's come in handy and is usually covered from any possible water or debris by my bedliner.

 

8 years 141k miles... and now it will probably go out today DOH!! lol.