My 2003 Dually LB7 has me baffelled. Accelerates like a rocket with nice firm shifts at around 3100 rpm through 1st and 2nd gears. Hits 3000 in 3rd and it flattens out like it has a governor on it. Can back slightly off of the pedal and it shifts into 4th and accelerates fine throough 4th and into 5th. Though it might be my Juice module, so I pulled it off, same thing. Was able to get it to accelerate normally about 1 time out of 4. Truck has 115k on it, new injectors at 80K. Any ideas where to start looking?? Fuel filter??? Damn I am lost
:confused:

Start with the fuel filter for sure.

Sounds familiar. I'm having a similar problem, rocket ship one day, dog the next. For me, its not the filter. Jason, has went for a spin in my truck and that day it was behaving normal. It is frustrating though, to have a truck that runs well and then runs like a dog pile the same day :mad:..... Like its got a governor is a good analogy. Its like is just cant get the extra fuel to go. CP3???

I would start looking at fuel rail pressure and see what it is doing. I say if it is not in the filter its in the strainer in the tank stop up. Does it ever die? Does it lose prime in fuel system?

Sounds familiar. I'm having a similar problem, rocket ship one day, dog the next. For me, its not the filter. Jason, has went for a spin in my truck and that day it was behaving normal. It is frustrating though, to have a truck that runs well and then runs like a dog pile the same day :mad:..... Like its got a governor is a good analogy. Its like is just cant get the extra fuel to go. CP3???


My truck does the exact same thing...... My rail pressure is fine, new filters, injectors and rail pressure good. :confused: I'm about to pull the tank and check the sock.

i have seen a few guys with this same complaint. i agree with everything i have seen so far. fuel filter first, then check the rail pressure, then when all else fails drop the tank.

Just talked to the shop. Replaced the fuel filter and it seems to be running fine now under hard acceleration. They say I went WAY too long between filter changes. WIll give it a try when I pick it up. Keeping my fingers crossed. Thanks to all for the advice.

Keep us posted...

I had the EXACT same symptoms. Looked it up on this board (searched it) and others were having the same problem.

The solution is to replace that fuel filter.

The problem will magically disappear.

Could it happen if I just changed the fuel filter like 2 weeks ago, useing the same gas as always..?

if you got a bad batch or a bad filter then yes. but there is only one way to figure that out for sure......

Well guys, that did it. Running great now. Need to pay a lot closer attention to my fuel filter interval. Thanks for all of the tips.:cool:

You're welcome! I love simple solutions!