eddies55

still a newbie on this site but i need some help. i have an 02 s55 and i recently did a tune up on the car. it just hit 100k miles and today i thought i felt it running kinda slugish but then it was back to normal. after filling it up with gas start running like crap with a really rough idle soon as that check engine light came on i plugged my scanner in it said misfire bank 1 cylinder one but i just changed the wires and the spark plugs soon as i shut it off and started it back up everything was fine. could it be maybe a bad coil or loose wire any kind of information would help