What do you think?

[bwillis]

I have a 2011 yukon XL.
It started misfiring. OBD said it was in 5.

We have changed plugs, wires, 2 coils, new battery, and now the Break Booster Sensor.

That has helped some. But still misfiring.

Had anyone ran in to this issue? What helped? Fuel filter? Any thing else?

 

[j91z28d1]

how bad is it missing? any ticking along with it?

what's the miles? afm should be #1, 4,6 and 7. so 5 should be normal but could be other valve related things. recently was a broken valve spring for one guy, others have had a valve seat fall out of the head.

a compression test might help, along with pulling the valve cover and lock for something out of place, like rocker arm loose when it shouldn't be.