You possibly have warped brake rotors on the front. Or Bad Wheel Bearings.
A car's steering wheel will vibrate when driving if the car's alignment needs to be adjusted.
Steering wheel and brake pedal.
bad front brakes.
get a wheel alignment
Warped rotors
It is the engine that is vibrating and it is just being felt in the steering wheel. Can be a vacuum leak, or miss in the engine.
the motor mount is bad
Normally it is a tire out of balance. Can also be a bent wheel.
Most likely warped brake discs
Normally this is caused by a tire out of balance or a bent wheel.
yes
could be a blockage in your fuel lines.