Hey Guys My Gf has a 06 4.0 stang and it has 55,000 on it .. the other night she said she was racing someone Idk why lol .. and the rmps shot up and the car died and won't start again. She took it to checker auto part to get the obd 2 read and the guy said 02 sensor but he also cleared the code like a dumbass so I can't do it myself .. any suggestions or similar experiances
, but I was pulling onto the freeway and suddenly the rpms shot up and my check engine light came on after a pop came from under the hood on the passenger side. I immediately pulled over and popped the hood. Everything looked fine, until I pulled the timing belt cover and there it was in two pieces, the timing belt. 
The only thing that I can think of that would jump the rpms like that are drivetrain loss somewhere. Which can go from engine to the hubs on the rear wheels. 