99 Tahoe New Fuel Pump, Runs Fine Cold, Struggles to run when warmed up

[texdod]

I have a 99 Tahoe 4x4 that has a new fuel pump in it (from Autozone). The new fuel pump solved the problem of not starting, and the truck ran fine for maybe 3 weeks. Now it starts and runs fine until it gets warmed up, then it starts stalling out like it's starved for fuel. If I keep driving it when it starts to act up, it gets progressively worse until it will barely idle (any throttle will kill it). However, if I turn the engine off and immediately restart, the situation improves dramatically (if I restart, it runs good, but not perfect). So now I have a truck that I can drive, but I have to restart every 7 or 8 miles to make it keep up with traffic. When I did the fuel pump, found lots of water in tank, but cleaned the tank out good.

It has relatively recent tune up (plugs, wires, cap, rotor, fuel filter). Could water in the fuel cause it to act like this?

Thanks in advance!

[777stickman]

Welcome to AF

Check out this thread as far as fuel pumps and pressures are concerned.

http://www.automotiveforums.com/vbul...d.php?t=721790

[usamarshal]

Yeah, sounds like there isn't enough fuel pressure...mine was doing the exact same thing yours did...it took about four autozone fuel pumps before I said the hell with this sh!t and went with the GM/AC Delco pump...make sure to change the fuel filter too...Peace!!!

[texdod]

Thanks Stickman. I had read that thread - lots of info there, but I thought my issue was a little different. I found a parts guy today who seemed to be knowledgeable about these trucks, and he mentioned a couple of things. He thought there might be a problem with the "spider" (I have no idea what this thing is), or the O2 sensors. He came to the O2 idea after checking my computer and finding a couple of error codes that identified both of the front sensors not reporting.

Either of these things make sense?

[texdod]

Thanks usamarshall - that's good to know, but not really what I wanted to hear... Were you able to get Autozone to eat the bad pumps?

[texdod]

BUMP - HELP! This thing is driving me nuts!

[legbreaker]

If you have an autozone pump in there, I would go back to check the fuel pressure. It's very possible that it's intermittently failing.

[texdod]

It was the fuel pump. I'm getting pretty go at dropping the tank... The biggest tip I could give on dropping the tank is - do it with the tank empty!