Yesterday, soon after filling up with diesel, my truck began idling kind of rough and today the rough idle is accompanied by a noticable knock. It has never done this before.

Since it started right after I filled up I thought maybe it was bad fuel. I put a bottle of Diesel Kleen in thinging that might help, but it hasn't gotten any better (in fact it may have gotten worse).

What else could cause this? Could it be an injector going bad?

The truck has almost 78,000 miles on it and has been pretty much trouble free so far.

 

Hoss, after reading your post the other day, I think it might be a duramax hiding under the hood knocking to come out .

 

Hoss keep an eye on your oil to be sure it isn't getting fuel in it. Might be an injector....

 

ARTIST: Tony Orlando and Dawn
TITLE: Knock Three Times

Hey girl what ya doin' down there
Dancin' alone every night while I live right above you
I can hear your music playin'
I can feel your body swayin'
One floor below me you don't even know me
I love you

{Refrain}
Oh, my darling, knock three times on the ceiling if you want me
Twice on the pipe if the answer is no, oh, my sweetness
(Knock, knock, knock!) Means you'll meet me in the hallway
Mmm, twice on the pipe (clink, clink) means you ain't gonna show

If you look out your window tonight
Pull in the string with the note that's attached to my heart
Read how many times I saw you
How in my silence I adored you
And only in my dreams did that wall between us come apart

{Refrain}

I can hear your music playin'
I can feel your body swayin'
One floor below me you don't even know me
I love you

{Refrain}

 

You're concrete bed liner isn't seperating from the bed is it? maybe the vibrations from the engine are causing harmonics to ring through the concrete?
Sorry i'll quit now, maybe some others can help out.

 

Well...I guess 1 out of 4 ain't bad. Thanks Lary. I need to change the oil this weekend anyway so I'll take a look at it. Is there something I should look for? If diesel mixes with oil isn't it still just black??

This morning it was still idling rough and there was still a noticable knock that seemed to knock louder and harder when I first started loading the engine while taking off. It still seems to run fine going down the highway.

 

Sounds like an injector tip is fouled with carbon. Take it out and run the dog snot out of it (drive it like you stole it).

MikeyB

 

Hoss if you lose an injector it will be flooding the engine with fuel. You will notice that you have more oil on the dipstick than you should it will be over full. Try Mikeys idea and run the heck out of it that might help.

I like mikeyB's motto...."When in doubt, Floor it!"

 

While you are drive the heck out of it add a can of Sea Foam. It's a pretty good injector cleaner.

Also, trying dumping the fuel from your water / fuel seperator and see if there is any foreign stuff in it. Catch it in a glass jar and let it sit.

Like Lary said check the oil level right away and see if there has been an increase in the level. A sure sign an injector pooped out or you have a truck making it's own oil.

 

Hoss are you sure you didn't put gas in it ? If it was not knocking before fill up and is after my mind thinks it got to have something to do with the fill up .

 

Could be a tank of bad fuel as some have suggested. Good luck with it Hoss, long time no see!

 

Two things that can happen: Some yukkies get in the injector and cause it to stick slightly or it is failing internally and not sealing properly.

I dont see many that can be catagorized as sticking from poor filtration.

Its under warranty @ 78K, so a trip to the dealer might get you a new stick (:

 

Put a can of Sea Foam in it

 

I tried that last night on the way to church...and on the way home. I got it up to 80 in 5th gear...about 3200 RPM's. Didn't really seem to make a difference, but I'll try it again on my way home today (as much as you can in rush hour traffic).

I'll check the oil level this afternoon before I crank it up to drive home. I know right where it normally sits when full so if it's high I should be able to tell.

Well, I'm sure I used the diesel pump, so unless they put gas in the diesel tank then that shouldn't be the issue.

I want to believe it's bad fuel since it started happening right after I filled up. I don't really want to pay to replace an injector right now.

Yeah...where ya been??

I thought the engine and drivetrain warranty cut off at 70,000 miles??

Where can I get this Sea Foam stuff? Will it hurt it to have Sea Foam AND Diesel Kleen in there at the same time (I dumped a whole bottle of Diesel Kleen in...enough to treat 100 gallons).

 

Hoss,

Are you anywhere near Parmer and I-35 in N. Austin. I'd like to hear it.
What station did yo use?

Pete