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Discussion Starter #1
2003 duramax 45000 miles allison tran,hypertech installed.
one day the truck runs perfect then on some days if i put the pedal down the truck like stalls above 2000 rpms like it is starving for fuel.i have changed filters.no help like i said one day fine next day problems cant figure it out help!!!!
 

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Read some of the posts, or do a search, you may find that the first suggestions are going to be to measure the commanded vs. actual rail pressure at wot, tech II works the best, but some other programmers will read this information,
I did have a similar problem with my 02' LB7, wound up being a rare weak cp3 pump, with large tunes it would drop clear down to 13,000 psi and should have been more in the tune of 19,000 to 21,000 psi.
Could also be the fuel pressure regulator which is attached to the cp3 pump.
When i took it to the dealer with all tuners etc. unhooked it would no reveal any problems though, so i had to change it myself, Eric Merchant hooked me up with a new cp3 pump and regulator, great ever since.
Good luck
 

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also, before you get too carried away, look for ANY place where air could be creeping into the fuel system. I had a similer problem, ran fantastically some days, not others. finally noticed a connection between good running days and bad, and the ambient temperature. turned out to be a small amount of water in the filter drain, it would freeze and expand, stretching that white plastic just enough to let air past the o-ring into the filter. I have also had trouble with the bleeder on the top of the filter.
 

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That happened on my 02.It would fall on it's face when accelerating hard.I have the bullydog powerpup. Mine ended up being a weak cp3 also.At full pressure it would only reach 12000 psi.Put a used pump my buddy had and it runs like new.You might have someone with a tech 2 check your pressure.

Jon
 

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Possibly injectors. Is it smoking at an idle or fuel in the oil?
 

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same here

I just started having the same problem. Ill hit the gas and its like the truck stalls around 3000rpm. i have to let off the gas to get her to shift. My check engine lite then comes one(occasionally) I then get a C086B code on my superchips programmer.
 

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Discussion Starter #10
that is exactly what is happening to me but mine sometimes occurs around 2200 rpm what is wrong?
 

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i had a similar problem. Finally the truck would not start one day. It had lost prime. Found out the filter housing was leaking a small amount at the plunger and where the fuel heater plugs in. The tech at the dealer said this is a common place for a leak to develop. I noticed it more in the high Edge settings.
 

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Where are you located? Temp related perhaps? Mine has done that recently also but then it was about -20 outside.
 

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mine has been doin that stalling/backing down also. i'm going to change the fuel filter this weekend and see if that helps.
 

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misley;1582796; said:
Where are you located? Temp related perhaps? Mine has done that recently also but then it was about -20 outside.
Absolutely agree mine does this until all the fuel is warmed up. Takes about 20 minutes for a full tank to warm up, Go for a long drive then try again i bet your problem disappears.:)
 

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Check for codes!
 

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Still trying to figure it out. Lets keep each other posted.
 

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Discussion Starter #18
went to dealer told him the problem.he said he had 15 duramaxs in the shop in the past two weeks.problem is the fuel filters!!!it has been cold here about 20 for the past two weeks.but i use power service.BUT they still told me to keep changing filter.they said they have a new revised fuel filter that just came in it is colored blue this time if that means anything i dont have the new parts # yet.i guess i will change the filter again and see if that helps.
 

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If you find out more info about ther revised filter let us know. I am a bit weary of it. Seems pretty basic that the finer the filter the more it will filter but the more it will gel and vice versa. Sound right?
 

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I'm here in Hawaii, I have a 2001 and I get that problem, but mine is with a load, every time I haul a load up a decent grade, I'll lose my power for about 15-20 seconds and then it'll kick back in. I too changed fuel filters, but that didn't solve the problem. I am running the banks six gun, problem happens with it hooked up or not. No codes either.
 
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