I'm hoping someone can point me in the right direction. My fuel pressure @ idle sits @ 21psi, in the pass few days it will suddenly drop to 15 psi. I'll shut down and re fire and it will return to normal. I'm running -6 an aeroquip lines from the tank to a Holley Red Pusher which
should give me about 6 or 7 psi to the stock carter lift pump. I disconnected the ground on the Holley for a few seconds and the pressure fell to 0. I thought the Carter would pull fuel thru but thats not the case. The Holley is warm and humming, but that doesn't mean anything except she got juice. I suspect its the Pusher Pump going south, but thought I'd check with the Diesel Crew for their expertise.

Thanks Mike

 

When i was running a holley behind my stock pump, i eventually had fluctuating pressure too. I found it to be the stock pump starting to give up. One other problem i had was the isolator for the fpg. It would start to act up after being on a year. Drive it till one of the 2 pumps quit and put a real pump on, fass or walbro.