First of all i am female...dont know to much about cars. The other day i was going about 65 mph and my car just cut off....I got it to the side of the road and it started up but then cut right back off. Then about 6 hours later we went to get it and it started up fine. The next day it did the very same thing. But this time it blew a big puff of black smoke out of the exhaust pipe. I changed the fuel filter because thats what a mechanic said it was but it wasnt....it still doesnt work. If anyone has any suggestions please let me know. thank you.

Have you checked your fuel pump? Sometimes a faulty fuel pump will act erratically, most newer cars have the fuel pump in the gas tank now, next time this happens try tapping the tank lightly with something firm, maybe use an old shoe as not to damage the tank, turn your car into the "on" position, not fully starting the car with the key, and see if you can hear the fuel pump coming on. You can also disconnect the fuel line in the engine compartment and turn the key on and see if you are getting fuel, but be careful, and use a small jar or can, so as not to let fuel drip onto anything. If there is no sound, or any fuel coming out, more than likely it's your fuel pump that has problems.