The vehicle shakes now and then.
Unfortunately the information provided is limited. Normally I would investigate and see if your Ford shakes at certain speeds. If so, then shaking now and then could be the result of unbalanced tires. Next I would investigate if the shaking stops at the red light or does it stop under heavy acceleration. These could be a sign of lack of fuel in the SUV. Having clogged EGR valves can also cause your Explorer to shake, as well as having worn out spark plugs and worn out shocks. Since more information is needed, it is best to have a certified technician, such as one from YourMechanic, stop by and test drive your Ford to confirm the cause of the vehicle shake and to successfully move forward with identifying the problem.