Check engine light P0301
 

Wonder what this is? (Cylinder misfire?)
Background: drove 250+ miles, stopped for gas, light comes on after about 10 minutes. I check the gas cap, all secure. Light stays on.
Take the car to Daytona Mazda, the good guys check the code, offer to replace the coil and plug under warranty on the spot, but we both feel maybe it was bad gas. They cleared the light, I drive it a bunch, no more light, so I waved off on the offer to fix it.
On the home trip, same thing again - 250+ miles into the trip, I stop for gas (Shell V Power), 10 minutes later the check engine light comes on. Check the gas cap, all tight.
Dropped it at the dealer this morning, they will check.
Comments:
It's not related to cold start - car was WELL warmed both times. It didn't show up in short trips. Seems maybe related to gas stops but not sure. Maybe a WARM restart issue?
Open for any thoughts -