Removed the TB, upper intake, EGR, etc. to do a good cleaning of everything this afternoon. No obvious problems, but I did notice the Idle Air Contol valve was partially open. Is this correct, or should it be in closed position? I ask because at idle my truck seems to stumble a little bit.

 

Not sure what position it should be in when it is removed, but I would go ahead and clean it with some carb cleaner....I had some issues a few years back and mine was dirty. I cleaned it and it seemed to help the problem

 

I cleaned it thourghly before re-installing, but still have the problem.

EDIT: I looked at a new one and it's in the open position.

 

Did you give it a quick blast of wd40. That helps.
What was your original problem?

 

Yes, I shot a little in there.

My original problem is at idle, the engine misses or jumps. It's just a slight hesitation every few seconds. I can't see it on the analog tach, but you can feel it. I took everything apart to clean and see if there was any carbon built up anywhere. It was very clean (after 175k miles). This was done in addition to a new fuel filter, air filter, cleaning the MAF, plugs, COPS, induction cleaning, etc. within the last month.

Popped a new IAC on without any positive results.

EDIT. I also replaced the EGR valve, DPFE and the EGR solenoid.

 

I know what your talking about, can even sometimes hear it in the exhaust if your outside. Mine does the same. Just an occasional bump here and there. Not sure what it is but haven't paid much attention to it since the truck runs great and as far as I can remember, every v8 I have owned does the same.

Could be a low grade misfire..? Not sure, again.. it may be chasing a ghost. If its the same little bumps were talking about. They are almost consistent, like every 3 seconds or so. Maybe someone else can say whether or not that's a misfire or somewhat normal. The motor I have in only has 12k miles. It is very clean with no carbon build up yet, everything functions properly and it still has that. Only think I would question on my truck would be the injectors since they sat for over 5 years. But they have had a few bottles of seafoam ran through the tank since operating again and seem to be doing fine now.

 

It hasn't always run like this. Just seemed to notice in the past year or so AND IT"S DRIVING ME CRAZY! along with the brakes that keep shuddering (3 sets of rotors and pads in 2 years) and wheels/tires that vibrate (2 sets of tires, balanced every 5k in 2 years)...


I hate to say it, but I got an appointment with the dealer Mon am to see what they can diagnose. I'll fix whatever they find though.