'04 LLY surge

Hey guys, need some help with my LLY.

'04 LLY, s&b intake, level, rims and tires, no chip, no codes that I know of, no SEL, everything else is stock. Just replaced a hub, not really any other work done to it.

Took the truck to a local shop to have the trans flushed, coolant flushed, and decided while it was there to have the fuel filter replaced. Got the truck back and it's surging (idle up), sometimes at idle but mostly when driving around. Has hard starts and sometime will die a couple minutes after starting it, when it does die, I have to prime the fuel.

From the research I've done I think it's due to either the fuel lines being corroded or when the shop replaced the fuel filter, they messed something up. So I decided to wait a couple of days to see if it would develop a fuel leak but it hasn't. The truck has no leaks actually. Is there a way to test the fuel lines, or should I just replaced them and go from there? Thanks!


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Could be a coincidence, but maybe the lift pump is starting to go bad. If the lines were corroded through, you'd have fuel leaking. I don't know what's entailed on the GM filters.

How does it run while driving?

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Originally Posted by Polaraco

Could be a coincidence, but maybe the lift pump is starting to go bad. If the lines were corroded through, you'd have fuel leaking. I don't know what's entailed on the GM filters.

How does it run while driving?

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It'll run fine until it starts surging, when it starts surging it'll lunge forward. But other than the surging it doesn't do anything out of the norm


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Originally Posted by levimeloy

It'll run fine until it starts surging, when it starts surging it'll lunge forward. But other than the surging it doesn't do anything out of the norm


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Better check out that lift pump. The CP3 will draw fuel, but low quantities. They depend on the fuel to lubricate them.

Quote:

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Originally Posted by Polaraco

Better check out that lift pump. The CP3 will draw fuel, but low quantities. They depend on the fuel to lubricate them.

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Is there a way to test the lift pump?


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Quote:

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Originally Posted by levimeloy

Is there a way to test the lift pump?


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I'm sure there is. But I am afraid I don't know how. I'm a Dodge guy and really good at them. The principles are the same. I'm a moderator borrowed from Igotacummins. I help where I can here.

I don't know if there's a port on the line or not on the GM. I was kind of hoping another member would chime in. But I'll do some research

Quote:

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Originally Posted by Polaraco

I'm sure there is. But I am afraid I don't know how. I'm a Dodge guy and really good at them. The principles are the same. I'm a moderator borrowed from Igotacummins. I help where I can here.

I don't know if there's a port on the line or not on the GM. I was kind of hoping another member would chime in. But I'll do some research

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Ok thanks. Yeah I get what you mean lol, i own a 7.3, and can wrench on it no problem. This duramax is my stepdads and he's never had to work on it. It's a low mile truck, been used to pull a bass boat around its whole life.


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