IT COULD BE SEVERAL THINGS, 1 THE TIRES ARE NOT BALANCED IF ALREADY DONE THEN BRING IT BACK AND SEE IF ANY OF THE COUNTER WEIGHTS HAVE FALLEN OFF IT HAAPPENS, OR ONE OF YOUR TIRES STEEL BELT HAS BROKEN AWAY, 2 YOU MAY NEED A FRONT END ALIGNMENT, 3 HAVE TIE RODS, AND ALL STEERING RELATED PARTS CHECKED, THEY DO GO AND WILL CAUSE A SHAKE IN THE FRONT.
Carburator problems -- dirty gas -- water in gas
Nobody could answer that question without looking at your car. One of the possibilities is that your car is overheating. Check the coolant. By the way, if this is the case, and you are driving your car without coolant, stop driving right now because your car is in danger of being irreversabely ruined forever.
Rotors are warped. Have them trued or replaced as necessary. Also replace the brake pads at the same time.
Your tires probably just need to be balanced.
If your car shakes while underway, your tires have worn incorrectly from misalignment. If it shakes while in park or not moving, your engine is misfiring.
Your alternator is not keeping the battery charged.
Need more info like what is the vehicle doing when it shakes, is it idling in park, driving down the road, braking, driving at highway speeds, etc.
Engine miss.
Your car is not getting enough fuel if it hesitates to take off and shakes. The fuel filter might be plugged or you might have the wrong gas in your tank.
When the engine light comes on and the car shakes at the same time, it could be the spark plugs or ignition coils are faulty. Misfiring is causing the car to shake.
Drive shaft is going out
It normally means you have a bent wheel or tire out of balance. Have your tires rotated and balanced.