09 Yukon Cyl 5 Misfire - SOLVED

[j91z28d1]

Yup, put them in and it runs great! I cleared all the codes and none have come back yet. I would have never thought about counterfeit plugs, especially since they were AC Delco. I gotta wonder what else is out there that is no good!?!
Thanks to everyone who chimed in!

glad it was something easy ish.. such a shame all these parts are junk.. they sure look real but are worse than no name auto parts store stuff.

painful.