I dont know what it is but my truck seems to idle a little rough. only when it is just sittin there. not runnin or anything like that. When I check the codes none show up. but it seems to miss or something only at idle. any suggestions on what to check would help. I know it isnt the fuel filter cause I just changed it. about a week ago. And every time I call n ask the dealership they just tell me to add an additive to the fuel and I have been but it doesnt really seem to help. some one please chime in

 

Might be bad injectors. I had the same problem earlier this year and had to have 2 injectors replaced. Try a little 2 stroke in your fuel too. It might help.

 

Normal. Mine does the same thing. I believe it's that 3rd injector cycle.

 

I am also beginning to think it is "normal". I have been dealing with it for the last 12,000 miles and the dealer cannot find the issue. Mine is only when hot though. What is strange about it is that everyone I have heard it from has an '06, and it seems more prevalent with the G-56 trucks.

 

Mine did the rough idle thing once a year ago at around 9K miles. I dumped in a mix of 16 ozsMMO/16 ozs PS to a full tank of diesel. Lost the rough idle pretty quickly. Since then I have been running that mix in every tankful only cut it to 8 ozs each, no rough idle again.

My neighbor was complaining about rough idle this last week in his 2006 at about 25K miles on the clock. He did have it sometime last summer, 8-9K miles and used the same mix as I do. Difference is, he only dumped it in them and did not continue with using it like I did. He has done the same thing again-dumped in the 32 oz mix on Monday. I saw him yesterday and his rough idle is now gone.

He has the auto, I have the G56, so it obviously can happen to both model tranny trucks. Interestingly enough this seems to be a fall thing for both of us last year, him again this year, mine has stayed gone using the MMO/PS mix. Maybe it IS relevant to a dirty injector?

Another fellow I know with a 2006/auto tranny, had the problem at 5K, last spring a year ago, he is using the Valvoline injector cleaner regularly with every tankfull, same results as me, rough idle is gone and has stayed gone.

All 3 of us get fuel from the same place, it has new tanks and new pumps, also this supplier owns most all the diesel stations in the area, so again the same fuel is being supplied to them all. I am the only one who has traveled out of state and used fuel from many sources. We all change our fuel filters regularly, oil regularly, etc. I had the flash for white smoke, they had it and a couple others. I have the 2-micron GDP fuel filter add-on, they are stock. I also have the Amsoil BMK bypass filter, they are stock.

Maybe too much information here in my post, but at least it's 3 trucks that get used very much the same way and are using the same fuel.

Carol

 

rough idle on g56 is dmf off center,both mine went before 70k

 

DMF?????????

 

not to ask a dumb ? but what is 16 oz of MMO and 16 oz of PS?

 

nevermind I got the mmo marvel mystery oil but PS what is that?

 

PS = Power Service fuel additive.

 

whats the dmf?

 

where do you get the ps additive?

 

Wallymart!

 

dmf = dual mass flywheel I believe....