I noticed recently that sometimes my truck hesitates when accelerating. Lastnight I noticed that when wide open it sounds like a knocking noise. No codes are showing up and I'm not sure where I should start looking. As a side note a few months ago I replaced my injectors and noticed my lower intake bolts were loose so I just tightened them up and truck seemed to run fine.

Any help would be appreciated

 

sounds like theres some carbon build up in the cylinders

 

I thought the same as well I have... MAYBE 30,000 miles on my rebuild so... I'm not sure. I guess sea foam it anyway and see how it goes?

 

yea see what that does...make sure you change your oil and plugs afterwards

 

Nope no difference. I'm shocked this ain't pullin a code

 

Forgive me for brainstorming and correct me if im wrong but, A crap spark plug or ignition wire would throw a misfire code... A bad 02 would throw a lean / rich / lack of switching code... What about a vacuum leak that would throw a lean code right? It idles fine when warmed up no surging, on cold start there sounds like a slight misfire though... The coilpack i replaced with the motor along with every sencor (other than o2's) my has mileage seems correct getting 18mpg with a 4wd 3.0.... I'm stumped on what it could be

 

?

 

Bump
I replaced the egr valve no difference, I've checked my vacuum lines and they're all connected fuel rail, back of intake Mani, the two that go into the EGR solenoid, top of EGR, and the two "main" ones that lead away from The motor on both left and right sides, pcv valve is good and the tube is clear, DPFE was replaced. Plugs, wires, and coil pack have 30,000 on them

To be more specific I really notice the sputtering when I'm
In final gear and the torque converter locks up. It'll sputter between 2100 RPM through 3000 rpm when the pedal is depressed more than half way... If I'm above 3000 rom and I floor it I think I hear it ping along with sputtering but it's definitely lacking power. A local shop put it on a Snap-On Modis tool and all they found was the short term fuel trim was reading -1...

 

I wouldn't hesitate to recheck the plugs and wires. A bad plug may not throw a code. I just shared an experience in another thread where my truck started sputtering when I was pulling hills. after a while it started sputtering on flat road at higher speeds over 55 and above when trying to accelerate.(progressively getting worse over time) It turned out to be the plugs. My truck threw no codes either.

A friend had a similar experience on a different vehicle his problem turned out to be the cat. Scotty Kilmer has a good video on YT showing a non invasive way how to check your catalytic converter it's worth a look

 

Hmmm, maybe I'll just replace them since their $2 each. My one friend seems to think it's the cat too but wouldn't the rear o2 spit out a non sufficient efficiency flow code I'll search the video right now thank you!

 

I don't feel like drilling holes in my exhaust lol but someone said to unscrew the o2 that's in front of the cat and see if it runs better (thus telling me the cat is clogged) ...

 

If a head gasket is installed incorrectly or without dowel pins, it can be off center and cause pre ignition.

Run a tank of premuim fuel so see if the noise changes

 

I went over the plugs again and as I found a very small hairline crack in the number3 plug. I'm gonna change them all out with new wires n see what she does

 

There's more than one way to skin a cat
Another wayabout halfway down the page there are instructions by using engine vacuum and other methods.

 

I'm definitely saving that link for those methods! Thank you Skid. As for the plugs: changed em out and so far the truck is running great