Q: When I start my car, it shakes and smells like gas.

You could be getting a fuel smell from a fuel leak, or you might be getting a raw gas smell in the exhaust. Since you seem to have a misfire, I think you might be smelling it in the exhaust. Sometimes with older cars the injectors will start to leak from the tip. The fuel drips into the engine while the car is shut off and then, when you start the car there is too much fuel in the engine to burn well. The engine will misfire and shake and raw unburned fuel will come out of the exhaust. Of course this is just one possibility. There could be a number of other things causing the problem you describe. You can probably solve this problem most quickly by contacting Your Mechanic about having a technician come to your home or office to check out your fuel smell and your misfire and tell you what it will take to solve it.