So the first time, I was idling at a stop light and the truck just turns off and won't start again. It just cranks and nothing. So after twenty minutes of waiting for a friend, I give it one last shot and it finally fires up. Drive it immediately to the gas station. Put 19 gallons in the 26 gallon tank. Similar story last night, cruising on the freeway and the truck turns off. Get a gallon of gas (they only had 1 gal containers), and it will sputter for a second then die. My thought is that it needs a few more gallons to be picked up, so I get two more gal containers and I dump them in (4 gals added thus far). Still won't stay on. Well after the tow truck pulls up, I give it one last shot and it fires up. Drive straight to the gas station and put 15.3 gals in, meaning 10 gals were already in there.

Is my fuel pump going out, or problem with my fuel pickup? I am completely stumped. Around town and on the highway, it drives perfectly, and my fuel trims have always been spot on.

Here is a video from last night where it will fire but then immediately die:

Out of gas - YouTube

 

Sounds like a bad fuel pump to me. Don't you have a fuel pressure gauge?

 

I had a problem like that after I installed my AM340 fuel pump. Turned out the bucket wouldn't fill on it's own like it did with the walbro just stuffed in it so I had to cut the bottom out of it and set the pump screen on the bottom of the tank.

 

I think he's still on the stock Flexfuel pump. Could be mistaken though.

 

I do, kind of. The fuel pressure sensor the goes on the fuel rail doesn't work (found this out after I installed everything and wired it up), and I have been reluctant to drop $70-80 to buy a new one (the gauge was purchased used on PT).

And KB, I'm still on the stock FF pump and the tank has never been dropped, so I doubt that would be it, but either way, sounds like I have to drop the tank.

 

You are correct

 

Replace the pump.

 

That's what I'm thinking, especially since I replaced the fuel filter a few months ago. I was hoping someone would say, "sounds like a relay going bad" or something cheap and easy

Should I go with a direct replacement OEM flex fuel pump, or go with a Walbro or something aftermarket? The FF pumps flow well and have been able to keep up with my 75#'ers, so I am hesitant to change to something potentially less reliable.

Also, if anyone has the part number for a flex fuel pump with sender, that would be awesome! Haven't been able to conclusively figure it out.

 

I'd go with the OEM module in your case. GM part number is 88966962, Delco number is MU1378.

 

How's that AM340 working for you? Have you found its limits yet? Could you elaborate on the problem you had with the bucket not staying full, and any other issues you have noticed? I'll be installing one of these soon, so your input will be appreciated.

Oh, and......