Petrol does not have a high enough energy density. If you have enough of it on board to provide the energy needed to reach orbit, the vehicle will be too heavy to lift off.

It depends on the size and weight capacity of the fork lift in question. Also, unless you are speaking of a licensed and road-worthy vehicle which operate on the public streets, I do not believe that the light or heavy commercial status applies.

No. They launch in a space vehicle.

Polar Satellite Launch Vehicle was created in 1993.

It was launched from the launch vehicle at Cape Kennedy.