I recently acquired two more trailblazers and one running and driving just been sat up for I would say 2015 from last inspection in Mississippi. It has a gutted cat already probably from the code but it misfired on the way home and when I got home I hooked my scanner up it was random multiple misfire I replaced the plugs it hasn’t done it since but it still has p0016 code and engine idles a little rough. Any advice it greatly appreciated!