OK guys, this is my second winter with my LBZ. Last winter I had no issues with my truck at all. But here lately on the colder mornings, like below 50, when I go out on the road, the truck will not accelerate at all. When I try to it shifts and then acts like there is a governor on it. Then all of a sudden it goes like hell then it stops and so on. It has never done this before.
What is it doing? Once it warns up, it runs good. I have also had this happen while it is hot too. WTF? Is it this phantom I have been hearing about that the fuel pump or the Fuel computer is taking a crap on me?

Have you changed your fuel filter??

yes my first thought also is leaning toward a fuel filter. or your loosing boost some where EGR???? but i see you have that blocked...

Change your fuel filter.

how long since the last fuel filter change? diesels also just run a lot better when they are warm too.

Change the fuel filter. Are there any codes for EGR or low rail pressure?

I've noticed my truck doesn't have alot of get up and go until the engine and transmission warm up. I take it easy until she warms up.

I agree that I need to change my fuel filter. I just changed the nictane about 1000 miles ago and it has been about 15,000 since my last OEM filter change. I will see if I can get that done.
I get no codes at all. I can even leave my foot in the same position when this happens and it will surge faster for about 3 to 5 seconds, then hesistate, then surge back up then cut back off. once it warms up a bit, it runs fine. No codes pulled out at all.

in the mourning let it warm up for about 15-20 minutes and then u should be fine

You need to allow the truck to warm up properly before you start stomping on the acclerator. Has a lot to do with temps and the computer.

If there is a loud roar that goes with the lack of power, it could be your fan clutch has not disengaged yet. When it gets warm and the oil in the fan becomes more fluid it releases the clutch. The fan draws a lot of hp from the engine, which might be the sluggishness you are feeling. JAT.

Like liftlawssuck said just let it warm up. Usually you can hear the fan release after 3 or 4 minutes.

I believe that your manual says that this is the normal operation of a cold engine/transmission. The computer is in control and waiting for things to warm up. check the manual for both the Duramax and the Allison.

It did not do this at all last winter. That is why I am concerned.

Update: It appears that chaging the OEM filter has fixed this issue. WE cut the filter open and it was only 25% dirty at the most. So we still have not figured out why this would cause the truck to be like this only while cold. One mechanic said it could be vapor locking in the cold due to moisture in the fuel and not enough to cause the sensor to through a code.

i do not know why, but for whatever reason my truck is running good. If it starts acting up soon, I will post again.

Plug it in too. that helps. And a good fuel additive helps also.

happy trails.

Update. It did it again today. this time I got a code and it was the P0101 MAF code. I turned the truck off and back on, and it quit. I used the EVO to remove the code and it did not come back on all day and did not hesistate.

Could this be a fingerstick issue, the AFE intake issue? Any ideas?

Update. It did it again today. this time I got a code and it was the P0101 MAF code. I turned the truck off and back on, and it quit. I used the EVO to remove the code and it did not come back on all day and did not hesistate.

Could this be a fingerstick issue, the AFE intake issue? Any ideas?

I have been having the exact same problem.

I believe it is the EVO causing these issue. I also have the fingerstick and blocker for EGR so the computer should not be seeing an issue I woudln't think??

I noticed it for the first time after about 8 months wtih the EVO on... pulling my camper the truck went into limp mode... and then corrected itself after a few seconds.

Now I am noticing it more frequently. The other day I took off from a light and it was like the acclerator was disconnected... truck would not respond.

I have removed the EVO and had no issues.

I get 3 codes, 1 mass air flow and 2 EGR.. I clear them but they come back instantly.

Come to think of it, I might be able to connect these issues to the latest software upgrade for the EVO??

it could be the EVO, but I am leaning more towards bad connections on the stick. It even did it when I put the EVO back to dtock, so it is not it as far as I can tell. i will email Edge about it.

thanks,
Doug

Mine does the same thing. It will not allow a 5th gear shift untill a certain temp is reached. Then its smooth sailing.

Update.
It was the Fingerstick issue that was cousing it. The power wire tap for the stick had gotten unsoldered a little and once it was re soldered and put back away, the truck ran fantastic.
I went to Fingers' house and he made sure everything else checked out too. My truck had not been running right for quite sometime and now that it is running right, it is hard to hold onto now:eek: It is definately back to where I wanted it to be.
Thanks Fingers, you are just way too cool to help me out like that.:ro):thankyou2

well, now that you know the problem thats good. I was going to say my 1/2 ton gasser does the same thing till the engine and tranny warm up. I'm sure it's not as dramatic as the diesels but still the same concept. cold = bad.