2001 Dodge Ram 2500, code p320!

Hello and merry christmas to everyone. Today (x-mas) I picked up my Dodge 2500 pickup to bring it home. It only has 13,500 miles on it and I filled it up with 89 oct (noted that I just picked up the truck). Since the fill up I drove about 10-15 miles and the truck stalled and I looked at the mileage reading and it said "p320" Does anybody know what this means?? thanks for the help!!

Don't be a fool, take it back to the dealer.

I wouldn't have even gone home, the second the light came on and the truck stalled I would have had it towed back there.

P0320: Ignition/distributor engine speed input circuit malfunction.