1996 k1500 4.3l

Hello guys!

So the parts came and it is done! Someone was certainty in there before me because instead of replacing the gasket, they use silicone… so it made the removal of the upper intake manifold a bit tricky. The other thing is how more robust the new injector tubes are, and so to make them go to the back it is a bit of a challenge because I was afraid to brake them… but it is done. So you were right, the truck is running so much better, but then of course there is still an issue.

Once I completed the repair, I drove and it was such a pleasure to finally have a fast reacting truck, but then, truck feels like gas is not getting through for about 3 seconds, then drive, then the same. This was happening on normal flat surface, then I noticed my gas gauge at a bit less than a quarter of a tank. So I fill her up, and I drove for at least an hour perfectly, until I reached a bit of a hill, and the same thing about the truck holding up would happen again. When I describe no gas going through is not like when you are running of gas (engine shaking), it was like the rpm goes down (slowing the truck down) regardless of the gas pedal be pushed down. I probably drove about 8- miles by now with no error codes yet.

Any ideas?

Did you know that the CPFI fuel system on your truck requires at least 63 PSI to blow open the poppet valves on the fuel injectors?


Last time I checked the fuel pressure on that truck was about a month ago and it was around 40 PSI. If the pressure is bellow 63 PSI to that means I have to replace the fuel pump?

That’s what supplies the fuel pressure.


OK, I want to make sure I am understanding this correctly. This truck has two lines coming from the tank, one of them has access port right before it goes into the injectors… that is what I should be checking the fuel pressure. Is that correct? and if its bellow the recommended number, then I need to replace the fuel pump. Or, just for kicks, maybe I should replace the fuel filter first? It is new, but the truck was not driving for a long time, so perhaps the new filter got clogged??

On your engine . . . the intake end gaskets ARE sealant

You’re supposed to lay a bead front and rear and overlap it a bit onto the intake gaskets

You’ve got a return type system . . .

One feed

One return

Forget it, it’s almost certainly not the reason for your extremely low fuel pressure

here’s what you do, no ifs ands or buts

deadhead the fuel pump

Get under the truck and splice in your fuel pressure gauge direcly after the pump, BEFORE the fuel filter

Cycle the ignition key a few times

What’s the fuel pressure . . . ?!

The reason I’m telling you to do this is because there’s a possibility your fuel pump is fine, but maybe you’re losing fuel pressure up front