Your ignition timing is WAY off.
car turn off when put in to drive i hit the gas an it starts shacking an turns off why?
clogged or bad catalitic converter
Your cold start sensor could be at fault, get a new one
You Should Take It To A Garage
Check your idle, your idle might be too low so it is stalling your car.
Pressure test the convertor. Perhaps others can add.
I think that when you press the button the light or LED turns off and when you do not press it the light turns on.
Need to know the year and what you are working on. NEUTZ.
probably..... NOT!!!!!!!!!
that is unusual, your spark plugs and spark plug wires need to be changed if its a gas engine.
could be transmission
So that it does not accidently get set on without intending to. I suspect this is a legal, rather then technical solution. Turning it off really turns it off. Pressing the brake does the same as the cancel button. It remembers the set speed and you can press resume to go back to that speed.