Q&A

I was driving in traffic, and when I started to pass, I was in the wrong gear so I shifted quickly to have power to pass..moments later, my car lost power and did a backfiring noise, then died. When I tried to restart it, I kept getting the backfiring noise, and of course the car will not start. Can someone provide a clue as to what may have happened? The car was recently tuned - new plugs, rotor, wires, fuel filter.
Thanks in advance