4.3 Vortec V-6 CPI: I have a replaced the fuel pump, fuel filter, fuel pressure regulator and the spider was replaced about a year ago. When the pump was replaced it ran for about 2 days then wouldn't start fuel gauge was reading low but when the the return line was pinched off it would build up enough pressure to start but when you let go of the line it dies so we replaced the regulator pressure was right started it and let it idle about 10 minutes, drove down the road was good till I accelerated and it acted as if it wasnt getting enough gas hooked it back up to the fuel gauge and it had lost pressure now 50 is about all I can get. Any idea's?????

 

It could be the fuel pump relay. Its under your hood right above the brake booster mounted on the fire wall. There 2 identical looking side by side relays. The one on your right side (if your standing in front of your truck looking back at it) is the fuel pump relay and the other is for your horn. Switch them out, if it cures your problem then just get another one at the auto store, there about 10 bucks new. Hope it helps

 

Any news?

 

What brand fuel pump did you put in it?