07 ford Mustang shake

I'm assuming the cooling fan you're refering to is the engine coolant radiator fan and not the a/c cooling fan. I can't imagine the radiator fan would pull enough load to cause the car to shake, but anything is possible. Those fan motors are considerablely small and I just can't see it causing the issue you're having. Newer cars like your '07 have a 12v motor and don't run off the engine. The shaking could also be when your a/c compressor is kicking on, and due to the head pressure on the compressor. When the compressor starts pumping the refrigerant, it levels out because the pressure on the evap side is far less than when it first kicked on. If this is when the shaking occurs, I suggest having it checked out by someone who's known for doing car a/c repairs. The compressor could be is the reason for the shaking. I agree with the answer Tom gave about smelling coolant. That would indicate a leak of antifreeze coming from somewhere. Question: "is the engine temp runing normal, or a little high?" Also, "is coolant fluid level okay?"