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Random sputtering...

Unit453

Unit453

Cruises comfortably at 140...
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I've been getting a sputtering at random intervals. Its happened a total of maybe 5 times in 2 years. At first, it only did it at idle. It idles rough and feels like its missing. Its got a noticeable lope to it and thats what initially caught my attention.

This morning I started it up and it was loping at idle but not like a big cam lope, more of a series of short lopes that seem to be effected by rpms. I'm running Hypertech 90 and just recently detuned from PPE 225. Its done this with the Predator as well and now for the first time with Hypertech. This leads me to believe that its not the tune, even know I've found several flaws in Hypertech's tunes. It kinda felt like a gas engine with a bad O2 sensor or a bad plug.

I'm not hard on this truck and I'm at 45k miles. I recently switched to Amsoil so I'm not sure WTF is going on. This afternoon, it was sputtering as I was driving it after it had been sitting all day long. It went away after 170 degrees or so. It runs great and has excellent power but something is off.

My fuel filter isnt that old with maybe 7-8000 miles on it. Its gonna be due here in a month or so. I have a functioning EGR valve (1st one failed and was warranty replaced), no cat and no CEL or stored codes.

Anyone know if there's a TSB for this or whats causing it?
 
I'd say Fuel Filter too, but like you said, it's been doing it for the past 2 Years. Did it always start doing it right before you changed the Fuel Filter?
 
I just cleaned out my air filter like 600 miles ago. I can rule that out. My fuel filter isnt that old and it dosent need to be changed yet. I will probably end up doing it anyways though.
 
The filter might not be bad mileage wise, but you could have gotten a few bad tanks of fuel that would have dirty-ed the filter quicker.

Unit453 said:
I just cleaned out my air filter like 600 miles ago. I can rule that out. My fuel filter isnt that old and it dosent need to be changed yet. I will probably end up doing it anyways though.
Click to expand...
 
Besides the fuel filter and since you're running a wetted air filter, it could be a dirty MAF sensor.
As a side note, I have gotten the idle stumble at first startup occasionally as well as at low speed driving a time or 2. Never knew what it was and it's so infrequent I haven't worried about it. But I'm all stock too. I just figured it was time to mash on the thing... just to clean it out of course.;) :D
 
Nick, I would try cleaning the MAF sensor too. If you overoiled the S&B, it could have fogged it up a bit. Not a bad idea when having problems like that.
 
Well, the filter isnt too oiled. In fact, I dont even have any cleaning kit for it. I washed it out and out it back in. I know, I know, but at the time, I didnt wanna use K&N oil and its gotta be flowing better than it did. I need to replace the filter though more than anything.
 
If it comes down to it I can meat you somewhere and we can log it with my V2 and upload it so the members here can get a better idea of what's going on if the simple stuff don't work for yeah. What your describing though sounds just like mine ran when I loaded in my first 20/20 tune. It would lope at idle, but more like a loaded up lope. It cleared out as soon as I hit the throttle though. Also try some 2 stroke oil in the fuel and see if that helps.
 
I've run that before and was told to steer clear of that stuff that these injectors are not like those of past generations. I'm not the expert though.

I'd meet up with you anytime you have a free few minutes.
 
I know that the LB7 guys talk well of it using it to help with fuel pressure regulators and injectors. I thought the only downside was if you had a cat on it, but I see you said you put it to the curb already.
 
Unit453 said:
Well, the filter isnt too oiled. In fact, I dont even have any cleaning kit for it. I washed it out and out it back in. I know, I know, but at the time, I didnt wanna use K&N oil and its gotta be flowing better than it did. I need to replace the filter though more than anything.
Click to expand...

Well I'm sure I know someone who has a replacement filter for you...and a cleaning kit too;)

Call me tomorrow and I'll get one coming for you free of charge my friend:thumbsup:
 
There was a TSB for a reflash covering a random lopey idle, black smoke and possible EGR related codes. It was a long time ago and covered the bastard 06 LLY's and early LBZ's from what I remember.

Mine did that a few times before they reflashed it back good lord 3 years ago. It would chug and sputter at idle every now and then which would shake the whole damn truck. This may not even apply to your truck, but thought I'd throw it out there.
 
I know Ive had a strange hiccup in idle every once in a great while. But it only happends for 3-5 seconds and goes away. Not anything major. Its hard to explain , but you can tell when it does it because its not the normal smooth idle, it has a little vib or shake to it. But it only does it if idling for several minutes at a time and not all that often.
I never really worried about it. btw, Im at 87k. If there is an ECM update, I may go get that done. I have the 6th gear shudder when cold also. (theres an update for that) but its done that since brand new, just been lazy about getting to the dealer.
 
2 stroke

Pepperidge said:
I run 16 oz of 2 stroke every tank full... and a healthy dose of Power service diesel kleen(silver);)
Click to expand...

I also run 2 stroke in every tank along with either 8 oz. of Stanadyne or Power Service. I take a 20-24 oz. Gatorade Bottle, fill it up with 8 oz. of additive, and fill the rest up with 2 stroke. I can really notice a difference with and without the 2 stroke. Much smoother and more even idle with the 2 stroke. I have not noticed any sputter in the idle. Maybe you got bad fuel?
 
2 stroke makes a huge difference for me.... on my most recent trip, my buddy filled up while I was asleep and didn't put in the usual gallon of 2 stroke; the difference in clatter woke me up.

Another vote for fuel filter... I've had filters start to go south as few as 4,000mi.
 
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