Changed spark plugs, now runs rough - thoughts?

STOP - you changed the battery? It will take a few days to week or so to re-learn how you drive, you’ll be fine after that. If your plugs were gapped from factory you are likely ok (always a good idea to check though)

 

Yeah, yeah, not fear mongering, but I should have said, "Might be an issue if you need to make an emissions warranty claim, if they can prove the use of such plugs or failure to follow the maintenance schedule caused the failure." What are you guys, a bunch of lawyers?

My point was to stick with what the manual recommends, then there is no question. I made that point poorly, thanks for catching that.