Alright I have an 03 Z with 99k miles and about a month ago I get a random misfire with the SES light on. The misfiring stopped once my engine warmed up and the SES light came off on its own 2 days later. Then the same thing happened again about a week after that. I then proceeded to change my spark plugs (ngk) to see if that would once and for all stop this random misfire. I changed my spark plugs yesterday and now my car will misfire for about 10 minutes then run normal, then go back to misfiring. While my car was on and misfiring i was moving one of the coil pack harness connectors and the misfire stopped and then started again when I moved back. Could this be a loose connection issue or something like that?

 

Try changing the coil pack or all coil packs the the harness too. This is a known problem all over the forums.

Good Luck

 

I ended up just unplugging the battery over night for a hard reset and the misfire hasn't came back yet

 

Nice, I hope it doesn't come back for you. Mine was a *****.