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2008 Silverado 2500HD
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Discussion Starter #1
The other day, I noticed when getting on it, the motor would cut out, like it didn't have enough fuel. I figured maybe this tune is a little too big, so I tuned it down to level 2. Reset the trans and all seemed well. Until this morning. I go out to the truck, and she starts up just fine, goes down the road to the interstate perfectly fine. Then when I went to get on it, HUGE hesitation. It kept getting worse and worse until it finally came to a stop and died on the side of the road. Got out to check the primer bulb, and due to the lift pump its nice and firm. Got back in and fired right up, still a little hesitant. Bought a new fuel filter and new bleeder screw, and put them in. Didn't help. Truck now will not accelerate. No codes poped up, injector balance rates are good, desired vs actual pressure is very close to each other. No smoke whatsoever, just seems like not getting enough fuel. Checked the lift pump and it is still working. Can't seem to figure this out and I need Isabel back!! :help

Edit: it will drive down the road a little, but when giving it anymore throttle than about 20% it just bogs down. Throttle Position Sensor still reading accurate as well
 

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Sounds like Injector pump... stealer charges 95.00 to check but all he does is pour on more pressure to the cp3 if it runs away then your fine if it bogs out then the pump is bad. I'm no mechanic but they showed me this when i had injector issues.
 

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2008 Silverado 2500HD
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Discussion Starter #3
That was my first thought but rail pressure is right where the truck wants it
 

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Are you watching rail pressure while driving or just at idle... also sounds like cp3

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sounds like the MAF sensor to me
 

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2008 Silverado 2500HD
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Discussion Starter #6
MAF? Really? Without a code?
 

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2008 Silverado 2500HD
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894 Posts
Discussion Starter #7
My MAF reading moves with rpm like it should. Now in neutral motor won't rev past 2000.
 

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2008 Silverado 2500HD
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Discussion Starter #8
Looking for help on diagnosing problem. I don't want to spend $700 bucks on a new CP3 if its not bad. Could this be caused by a bad TCM or bad ignition switch?
 

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2008 Silverado 2500HD
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Discussion Starter #10
Exactly. If its in that limp mode, still throws no code. If I shut it off, and back on, its out of limp mode but still hiccuping like no other. First Ill remove my lift pump and use stock fuel system. It may be sucking in air. If that doesnt work then I will try the MAF sensor.
 

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i thought i heard a while back, if you have a lift pump, there wont be any air leaks?? is that true?
 

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MAF? Really? Without a code?
yes its a possibility. Had a friends truck the the exact thing your talking about where it wouldn't rev pass a certain rpm and bog down if you gave it too much gas. Everything read fine and we were stumped for a bit. We.eventually cleaned the maf and it felt like a new truck after. I hope its the same issue for you cause.its a easy fix. Worth a shot.

are you able to drive normal at like 1/8 gas pedal?( minimal gas applied?
 

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Discussion Starter #13
Yes. Like I said it all started very minor. Now that I think about it that is the reason I put the lift pump on. On my way back from school yesterday it was cutting out on the highway and when I would stomp it to the floor it would coast down and die. If I was really careful I'm sure I could drive it. I'm beginning to wonder if a fuel filter head could be the problem.

As for blowermax, your less likely to get air in your fuel system using a lift pump. I currently run a PPE on the 01, and had to make my own fuel lines. For the lock collar fittings I just slid 1/2" hose over the ends and tightened down with a hose clamp. There is always a possibility that air could be coming through the pressurized side fitting under the hood. Just because air is getting in doesn't mean fuel has to be leaking out. I really doubt the pump is the problem because the truck would cut out without the pump as well.

Another thought, I wonder if my fuel filter head is bad. Could possibly be sucking in air from there, but as StealthBoogie said, the syptoms you just described sound alot like mine. I will try the MAF sensor when I get back to the house on Thursday. Thank you everyone for their input.
 

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Discussion Starter #14
Just thought I would bring some closure to this thread, as I believe I should receive the dumb*ss of the year award. So I ordered a new MAF sensor, and the idiots sent me the wrong one. I was working on another truck as well, so I just pulled mine out and cleaned it with some starting fluid. Once it dried, I stuck it back in and went for a test drive. The truck still cut out and stuttered like no other. She died on me and I noticed something, I couldnt hear the lift pump. I threw it in park and turned the key back on, and heard the pump winding. I thought, "What the hell?" So I get back to the shop and test my power source for the lift pump. Turns out, I was only getting power with the key on in Park. Wow. Switched my power source and made sure I got power in every gear, took it for a drive, and it's got its balls back! Thank you everyone for you input, and if theres a lesson to be learned here, its make sure you have a good power source for your lift pump, and test it in all gears!
 

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lol, glad your back up and running
 

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Lol nice, I love it when it's an easy fix like that it never happens to me though


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