If it's a car with a carburetor, the unburned fuel will go into the exhaust system. Usually it will explode, blowing out your muffler.
You will lose Power Steering, power brakes, etc. Not a wise move. It may also caused irreparable damage to the transmission.
it depends. if the car isn't moving, but the engine is still on, then yes the pistons are moving. if the engine is off, and the car isn't moving, then the pistons are still.
the timing is off
because the engine is still processing the oil for about 20 seconds after you turn the car off
If by "stop the engine", you mean turn the car off, then the answer is NO!
The main reason a car will slow down when the engine is turned off is due to friction, there is friction on all moving parts which converts the kinetic energy of the cars movement into heat energy.
Turn the Engine OFF.
Turn your engine off, check the gas cap and restart your car. If that doesn't work, be more specific about which car you have or check your owners maunal.
In this order only. Turn engine off. Depress parking brake. Turn engine on. Lights will turn off. To turn lights back on relase parking brake.
Give more acceleration when your engine becomes too slow to prevent an unexpected turn off .
get a new car
the AC is run by a belt that is connected to the engine. if you turn the engine off, the belt stops moving. No belt movement means no power for the AC. the fan will only blow air, not cold air.
Not all moving objects accelerate. In general, an object will accelerate if there is a net force acting on it. For a ball in the air, this might be gravitation + air resistance; for a moving car (once you turn the engine off) it might be the force of friction; etc.