2011 GMC 6.0 running problem: no code

[winter4ever]

So the inlaws came up to Alaska to visit for a couple weeks. They have a

2011 GMC 1 ton with the 6.0 gas. They have a giant camper on the back,

and under 2000 rpms it runs kinda rough. It seems to be worse when it is

under a larger load, but it kinda does it all the time, a small fluctuation in

rpms. It Doesn't do it over 2000 rpms. You can really hear it and you can

actually even see the tach move a little bit. The truck only has 5000 miles on

it and they couldn't find anything wrong at the dealership. The only mod is an

aftermarket muffler. Its not a huge problem, more of a big annouyance being

that it is a brand new truck! Has

anyone else had this problem? Thanks in advance.

 

[winter4ever]

I guess it just must be a rough running pile of garbage.

Maybe something to do with the variable valve timing, perhaps they are all

that way?

 

[slash]

theres all kinds of things that can go wrong just check the basics plug wires ect, if
there are no codes gm will not warrenty anything ,a scantool would be handy but if you dont have one try a shop around town ,,,when was the last oil change VVT motors are very picky about viscosity and having clean oil...

 

[fasta76]

I would try a higher Octane gas! Might be pinging??

 

[winter4ever]

Its definately not pinging, i know what that sounds like. As for the oil, I really dont think that could be it. He said its done it since it was new. Its got clean oil in it now... not sure what weight but im sure he puts in the right stuff. Im thinking its just the way these vvt motors are. The best way i can describe it is that it sounds like a boat with a big block going through some choppy water, it has like a 100rpm fluctuation it it when its under a large load.

 

[9 Iron]

i run a 6.0l in my half ton, which the only diffrence is its hopped up with more power and a aluminum block. I know when i run regular it is rough at idle and about 1800rpms. As well on cold start up its sounds like its got a giant cam in it for the 1st minute of running then cleans up. Premium fixes all these problems as well i get better milage.


Another thing to think is that the factory only comes with 6or8 fuel maps given a certain percentage of throttle and rpm, a aftermarket box one come with twice to three times as many maps. Mayby you are just running between two maps and getting a wierd effect.

 

[metcalf]

having the same problem on mine. Took it to gm and all they found out it was the ac copressor kicking on and off. Worse part is i thought what a bunch of bs. So when i feeling the surging I switched off the ac and it quit. I dont know why but it would stop. Seems like a bunch of crap to me but who knows.

 

[Osborne Performance]

we have 2 but our 11 isnt doing the surging what the gm dealer here did on the 09 is change intake gaskets they have a few that have left with loose intake bolts but i still notice it it is a fueling or computer issue the 09 does it when it is cold then it goes away but only when cold