The other day I was driving and up a small hill when I noticed I was losing speed and could not keep up 55 MPH. I look in the mirror and see nothing but smoke behind me. It did that eveytime I gave it the "gas" and I slowed to almost a stop and then it came back to life so to speak. I was just driving 55 and was not doing anything funny just climbing a very small incline. Was driving fine till then and after that 30 second spell. I couldn't hear the turbo like I always can normally when I was doing that. Sounded like it was not spolling. I have the flashpack on performance, have 25K on the truck with the same air filter it came from the factory with and the vac gauge not the least sucked in. 5K on the fuel filter. No SES at all which I thought was strange. Half tank of fuel. The only thing I did that day that was different was a pulled our gooseneck 20K trailer and a 260 JD skidsteer 5 miles from the farm to my house and then back when I was done with it. I know thats a no no but I never even when over 40MPH and any hill I climbed I used a lower gear and kept it at least 2500 RPMs as to not to lug it to help keep the temps down. No problem and NO I do not have gauges. The power and smoke problem happen 10 miles after I had unhooked the trailer and was driving just the truck. Any thoughts or comments you have will be helpful.
Thanks
Nathan

My first thought would be turbo, was the smoke black? Maybe the vanes hung? Seems it should have thrown a underboost code though.

fuel filter

+1 on the fuel filter.....and check for water in fuel

I was gonna say intercooler boot. Might check for a leak in the boots.

even though there is not a light on, there could still have been codes set. Some codes have to fail twice under certain circumstances. Does your superchips read codes? If so check and see if the ecm stored any. This sounds like a egr issue, or MAF sensor problem to me.

water in the fuel maybe? or could have been a air bubble lodge in the injector? if it was air or water in the line the duramax engine will manage to force it out the duramax engine is pretty good about riddin itself of air or water reason beind is my dmax runs on 50/50 water/methanol and it runs fine also check your water seperator on the fuel filter it might have some trapped water or air in it hope that helps you let me know if ti does

Thanks I'll check it out. Filter doesn't have quite 5K on it but that doesn't been anything really. These trucks are very touchy when it come to fuel filters. It was ALOT of black smoke. Like sun blocking. Looked like my LB7 with the PPE turned up. :ro) Thats what I thought was maybe the vanes hung up or something. I will go out and check right now for codes. I've just been so busy I haven looked at it yet. I just drove the jeep to work today.-:t Then a KW with a 3406 Cat. Man the dual 6" stacks sound good!;) I thought maybe I sucked a bird into the air box due to the PPE mod. Thats exactly what if felt and sounded like someone shut off the air. Even the wife noticed and if she felt it you know it was a sudden change in power.

Just checked and no codes although I think the programmer can only read hard code and not the soft codes as well like the Tech II can. So it may have thrown a soft code that the Flashpack can not pick up on. I think thats what I have read on here somewhere.

Don't go by the vacume gauge on the air filter housing, they are notoriously unreliable. I would say that with 25K on the original filter it is probably time for a change.

I was gonna say intercooler boot. Might check for a leak in the boots.
x2 you got fuel ie black smoke..

got boost? had a boot come off on me make tunes of smoke but wouldne go anywere:rolleyes:

Yes I know on the big trucks I have seen them clear plugged and never moved the vac gauge. I was looking up to see what other people were getting out of theirs miles wise and seeing if I need to change it. I knocked it the other day when I did the air box mod and very little came out of it.

even though there is not a light on, there could still have been codes set. Some codes have to fail twice under certain circumstances. Does your superchips read codes? If so check and see if the ecm stored any. This sounds like a egr issue, or MAF sensor problem to me.

X2..

Yeah but it was like a 30 second hic up and then was fine and was fine before. 10 mile after towing to the problem and 20 miles after with no problem. I couldn't hear any whistle at all when I had the problem. Very very slight hill so wouldn't have been making much boost at all trying to putt up the hill at 55. Well if I was low on rail pressure it could cause black smoke and no power. My LB7 would run out of fuel pressure and stop climbing but would still put out plenty of black smoke. If the atamization(sp) was not good enough for the fuel to be burn well it'll just put out smoke and have no power. Hard to tell what will fix it if it fixed itself. I hate come and go problems. That always sucked working on big trucks that the driver said it did this but doesn't do it now but wants you to fix the problem it no longer has at that time. And the discription the drivers give sometimes is useless.

what about the egr valve being stuck open?

what about the egr valve being stuck open?

Don't know. I'm sure the dealer will just say if its not doing it now they won't look at it.

speaking from experience, that sucks trying to duplicate customer concerns. I used to work in as dealership tech, and intermittent problems were the worse to track down.
'

By the way I am not trying to defend dealers, but alot of them get a bad name, due to situations like this.

If it happens suddenly enough to notice the change, and then it changes back to normal, you can pretty much rule out fuel filter or air filter.

it sounds like faulty vvt operation- black smoke is unburnt fuel- that why pulling trucks pour it out like no tommorow.they are overfueling the shit out of them!! like rgullett said intermitten problems can be difficult !!! if i was you i would change the fuel filter or drain the water seperator and drive it. it could have been a fluke thing? IF you can re-create the conditions then take it in. i work on heavy equipment and you would be supprised what a bad tank of fuel can do! and for how long!!! alge in the tank will plug a fuel filter in less than a day! im not saying that is your problem - my point is that you can pull your hair out all day on a problem and get nowhere .... so just drive it, and when it happens again lay into the throttle and listen to (for) the turbo.:D gauges would help though !!!! even a temporapy set up to monitor boost. hope this helps..... goodluck!

Vanes may have got stuck for a moment, or the FPRV was leaking/stuck open. I had an LLY that used to do that once in awhile. Symptoms were identical.

Intercooler

I had the same problem. I was pulling a trailer up a hill and loss of power and black smoke. If I hit the gas It would lose more power and deep black smoke (ALOT!). It got worse. I had the fuel filter changed and the problem went away. I don't know if its what caused it. I will have the fuel filter changed every time I have the oil changed. I'm now getting close to being due for anouther oil change and my problem came back again.