Jump to content

'15 GMC 6.0L 3500 Random Misfire 8700 Miles - Help


Recommended Posts

Re-posted from wrong sub forum, hope this is the right one.

 

Hello everyone. I operate a business and have several work trucks, most being 1-ton's with flat beds, with welding machines on the back. The last work truck I purchased was a brand new 2015 GMC 3500 with no bed. I installed the flat bed and put all my welding equipment on it here at my shop. The truck worked flawlessly for the first year or so.

 

I run a welding fabrication company and my rig trucks are pulled into shop and locked up each and everyday. Some days the trucks will be cranked up for 1-2 minutes and pulled out into the front of shop. In the afternoons they will be pulled back in and locked up. This could happen for several days in a row or maybe a week. Sometimes they will be run everyday on local jobs and run 20 miles or less. I take care of all of my equipment and do regular oil changes when necessary.

 

The particular vehicle in topic is a 2015 GMC 3500 HD with 6.0L gas burner (8'700 miles). It has passed 3 year warranty. It has had selected "bad" spark plugs replaced maybe 12 spark plugs in total. The truck would start running bad while driving and start to have a hiccup and bad idle/misfire. I would take it to the dealership and they would diagnose it with a random misfire in cylinder "x" and they changed the plug in question. The cylinder(s) were mostly different each trip in. I would receive the truck back, codes cleared, and the truck would continue to run like a top for several months before issues arose again. I would take it back and they would change the spark plug(s) and problems gone. I don't have the code on hand at the moment but I remember hooking it up to a snap on diagnostic tool and the code was random misfire. I vaguely remember the code being p0300. I have since bought OEM spark plugs myself once. I hooked up diagnostic tool and it showed cylinder #7 had a misfire. I replaced #7, cleared code and issues went away for months. The problem just came back again this week and I am near sick of changing spark plugs on a vehicle with 8700 miles on it. What should I do, what could be causing this issue?

 

 

Let me know if any more details would help.

 

 

Thanks, Bear.

Link to comment
Share on other sites

1 hour ago, MNorby said:

Maybe swap coil/wire with the one next to it and see if things change or follow. 

I can figure out which spark plug fouls out. I want to figure out why this is happening on an engine with 8700 miles on it.

Link to comment
Share on other sites

  • 2 months later...

How noticeable is the misfire? Does it throw a check engine light?

I have noticed on my '15 2500 that when the truck is idling it'll have a little misfire to it.... But it's almost imperceptible

Sent from my BBD100-2 using Tapatalk

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.