99 300M check engin light

Car seems to be running great. On the way home the other evening the check engin light came on. I had just purchased gas. When I got home the gas cap could still be turned a couple of clicks. The only other time the light ever came on was when I didn't have the cap on tight enough. I got a code of P0300. It isn't misfiring or running rough. How can I reset the light to see if it continues to come on. Or do you think it could be something else?

Not sure what the 0300 TRULY means. Random cylinder misfire. I would reset the codes and see what transpires. You can disconnect the battery for about 10-15 minutes and that works, or if it actually is a random code the light will disappear on its own over time.

I have a 2001 and the same thing happens. I blew a rod and replaced the engine with a rebuilt 8/15. chk engine came on a week later. took to a trans shop and had them replace the sol switch pack 8/26 . now codes 1776 and 1784 pop back up again. the default locks the speed at about 50mph and the car will rev really high. i have to pull over, turn off engine, sit for 5min and restart and it is ok. I heard this is a chrysler trend and will be hard to diagnose?