I had the exact same problem (but passing a different car).

Mine ended up being a P304.

When I pulled the plug, there was the white 'trail' from inside the plug wire leading out indicating that there was some arcing going on. The plug itself had a black line running up the side, looked like a crack.

Check your plugs and wires and replace if necessary.

That black line is a carbon trace, the spark will follow that line to ground because it'* easier to do then to jump the air gap.

just an update engine light went off all by its self

KSR - in St Marys?

You do realize the issue didn't fix itself, it is still present. Most likely enough drive cycles occurred w/o an issue (you stomping it etc) that the light turns off.

If you'd like to pull the codes and solve the problem, we'd be happy to help guide you.