2011 2500hd 6.0 misfire

[CamGTP]

LS stuff usually doesn't like Bosch sensors. Only run AC Delco/Denso sensors in these trucks.

[Jager]

do your plug wires have steel heat shields on them?  Try taking all of them off and running it.

I had the P0300 and it got to where it would not run well enough to get out of the driveway.  Was checking spark on #8 and was lucky to be in a spot that I could see arcing  between the heat shield and the plug boot on #6.  Took all the heat shields off and the problem was gone.  My wires were originals with 195K mi. and had checked for continuity and resistance, but no check for the insulation breaking down.  You got new wires so I don't think it is causing your problem, but it  is an easy test to try.

Edited August 15, 2022 by Jager

[2011 Lifted]

is it always #1 cylinder misfire. Going through the same thing on a 2011 6.0 with 209k miles and I’m thinking it’s possibly a broken valve spring, even tho compression tests fine. Did you ever get any closure on yours?

[casey.mikl]

Hello, I know it has been a long time since I have been on here. I since bought a new truck and this one has been collecting dust in the yard. I got around to working on it again today as I have a buddy that is buying it from me. Turns out this whole time, the fix was a DENSO 02 sensor. Part number 234-4563 for the upstream sensor. If anyone ever has a 02 sensor code and you need to replace the sensors. MAKE SURE AND USE DENSO 02 SENSORS. THE OTHER BRANDS DO NOT WORK. All this time and a simple $37 sensor on Amazon fixed all the issues this truck had. 

[carkhz316]

3 hours ago, casey.mikl said:

MAKE SURE AND USE DENSO 02 SENSORS. THE OTHER BRANDS DO NOT WORK. All this time and a simple $37 sensor on Amazon fixed all the issues this truck had. 

Lol. Denso is good, but other brands are ok too. You contradict your sentiments by purchasing from Amazon, which is notorious for suppling counterfeit parts (including spark plugs and o2 sensors; among other items) via their commingling practice. Your best bet for legitimate parts is going to be a brick and mortar store, or the dealership. Rockauto is acceptable as their shipping is directly from auto parts distribution centers and jobber suppliers.