Throttle
 

Hi, we was driving home on the motorway and missed a large truck tyre in the road, however did hit some debris. A mile or so later we was turning off onto a slip road, so had to change gears. However the revs/throttle appeared to stick. We pulled over when we could and there was loads of smoke coming from the exhaust. We turned off the engine and got out to see what had caused this but couldn't see anything. When getting back into the car it failed to start.
Any idea what could have happened to cause this please?
Its a Mazda 5 2008 plate. And there was no issues with the car until this point today. :confused: