Last night I was driving home from out of town. I'm in a 2010 Touring with 139,000 miles on it. I was about 100 miles from home when my check engine light started blinking. In the past, the engine light has gone off and stayed lit with the "check emission system" warning with code P0420. It usually goes off on it's own. But this time the engine light was simply flashing with no other warning or indication. The car was driving perfectly fine. I googled it and every post said to stop the car immediately. I had no choice but to drive another 5 miles or so to be able to pull over safely into a well lit area. I turned the car off for about 20 minutes, restarted it to see if the light would come back and it didn't. I still didn't want to chance it so I got a hotel with my young son and decided to deal with it this morning, Sunday. After asking around since it was a tiny Town and no mechanics were open, I was advised that as long as the car felt fine and the light wasn't on it was ok to drive. I drove about 50 miles when it started flashing again and about a mile down the road I was able to pull over. However as I was stopping the car I felt it sputter and jerk a bit and I turned it off as soon as I possibly could. I ended up towing it home, and after the tow truck driver took the car down, I had to drive it just to park it in a spot because the tow truck driver wasn't able to release the car into the spot. Just in those 10 or so seconds, the check emission system, VTM-4 light and flashing engine light came on and the car was sputtering really bad from the exhaust. No one can look at it until Tuesday and I am terrified that I did major damage to it in those 50 miles I drove it, even though it drove fine. All fluids and temperature were normal. The car felt fine up until the very second I shut it off when it started jerking. Does anyone have any idea what this could be? I did fill up and drove about 125 miles before the first check engine light came on. Any insight would be helpful.