Sorry if this question has been asked before.

When you turn the key to the on position should you hear the lift pump cycle, correct?

I am not hearing anything, pressure comes up to about 14psi after the truck is started. At idle the pressure guages fluctuates up and down about 1/2 psi. During moderate acceleration the truck stutters slightly in fourth gear.

I know my lift pump was weak and I am preparing to replace it, but did it just die on me?

 

Ryan,
The lift pump will cycle only when key is moved to the run position which means you must "bump" the starter. Just turning the key to the on position won't activate the pump. The fact that you have 14 psi at idle means that your lift pump is doing its job. If your pump was dead, your injection pump can pull a vacuum on the intake side, and you have 14 psi, so your pump sounds healthy. You need to worry most about WOT fuel pressure. This shouldn't dip below about 8 psi. It is possible to have 14 psi at idle and 0 psi at full throttle. Is your gauge mechanical or electrical? I would suggest putting a pressure snubber or needle valve before the gauge to eliminate injection pump pulsations which may be giving you the 1/2 psi. bouncing effect.
-Jason

 

I can hit 0 at WOT easily which is why I knew it was going bad. I have a Westach 0-30 PSI electrical guage. When I installed it, about 11 mo ago, my Idle was at 15.5 psi.

 

Ryan, Mine used to go to 0psi at WOT. It made me cringe. I still have nightmares about it ;D
-Jason
Have you replaced your lift pump yet or is this the original? My original pump died at 47,000. New one has been in for 4,000 miles.

 

This is the original, with just over 40,000 on it. I have a "replacement" on the workbench at home but was trying to plan the installation along with new lines for a time when I had enough time to do the job the way I want to, not as an emergency repair.