2004 Tahoe z71 223k miles. P0306 code. Cylinder #6 misfire detected.

[AlphaBrett]

Originally, I was getting the codes P0101, P0300, and P0332. Faulty MAF, Random cylinder misfire, Knock sensor 2 Low Bank 2. After changing the spark plugs, the MAF code went away, as well as the Knock Sensor code. As for the Random cylinder misfire code. It changed to specifically Cylinder #6 misfire. I cleaned the fuel injectors. And I’m still having the issue. Seems to act up moreso when I accelerate as opposed to idling. But it also will have a rough idle at times. Disclaimer: I don’t know much about mechanics. I’m trying to learn though. Any suggestions or advice would be greatly appreciated. Or if anyone else has experienced the same issue. And what they did or what I should do moving forward.
Kind regards,
Brett

 

[justirv]

Originally, I was getting the codes P0101, P0300, and P0332. Faulty MAF, Random cylinder misfire, Knock sensor 2 Low Bank 2. After changing the spark plugs, the MAF code went away, as well as the Knock Sensor code. As for the Random cylinder misfire code. It changed to specifically Cylinder #6 misfire. I cleaned the fuel injectors. And I’m still having the issue. Seems to act up moreso when I accelerate as opposed to idling. But it also will have a rough idle at times. Disclaimer: I don’t know much about mechanics. I’m trying to learn though. Any suggestions or advice would be greatly appreciated. Or if anyone else has experienced the same issue. And what they did or what I should do moving forward.
Kind regards,
Brett

You should be getting some responses shortly. What are the environmental conditions when this happens? Engine warm or cold, outside temp warm or cold? Intake manifold shrinkage is more noticible with temp variations. You can spray an aerosol of your choice to check for leaks. Good to see you have it isolated to #6, have you tried swapping the sparkplug wire? The coils on these "typically" don't go bad. Are you in an area known for corrosion? Bad grounds can cause mysterious havoc. Our local experts should have more suggestions for you soon.

 

[Fless]

You can swap the spark plug, spark plug wire, and coil (maybe later the injector) from cyl #6 with another cylinder. But do it one at a time, maybe jot down your steps, and re-test after each change. If the misfire follows one of those parts you have your answer. If it doesn't, then more diagnostics are in order.

 

[AlphaBrett]

So I swapped the wire, the plug, then the coil from the misfiring #6 cylinder to #4. And the CEL came back on. At first it was P0300. Random cylinder. But that soon changed back to P0306. So, it seems it’s probably the fuel injector? But I should do the same thing with the injectors as I did with the spark plugs etc correct? So if I swap them out, and the misfire moves then I have my answer. I’m really praying that’s what it is. Stay tuned.

 

[strutaeng]

Yeah, you can swap the injectors and see if the problem goes to the other cylinder.

I've never tried this, but I've read you can try listening with a stethoscope to see if the injector is pulsing. I think it makes like ticking sound.

Has the truck ran good otherwise? You know any history on it?