ndhole

I have about $3000 in two different mechanics trying to solve this code. I am not sure they are even looking in the right direction. Any help would be appreciated for ideas. I have researched the internet and found very little and explanations are all over the place. I live about 2 hours from the nearest MB Dealership so hoping to find just a good import mechanic that might have some luck. This is a 2013 GL450 with 79,000 miles. It has a rough idle but gas mileage seems consistent. Very well taken care of, all oil changes regular and filters.

Thanks,

EWT

You might get more answers in the X166 forum, but in doing research into 2013+ MLs, I've read that weird cylinder 5 issues can be an indication of a valve guide issue some M278 engines have. Over time the guide gets loose enough so the valve doesn't seal properly causing strange error codes: https://mbworld.org/forums/gl-class-...e-problem.html Hopefully that's not the case as it isn't a cheap fix. Good luck.

ndhole

Yes, I realized I put it on the wrong thread after and didn't see how to delete. Added it to that thread later.

Thanks,