Slightly off topic, but related...
I just did a simple sparkplug change on my wife's vehicle and now the car runs like crap off idle. Firing order is correct. My only guess is that I used NAPA copper anti-seize on the plugs, the heads were really grimy and I barely got the old plugs out, so I thought dab would be ok (plus its copper based). Could this stuff be messing with the grounding of the plugs?