Engine Mechanical problem
2000 Ford Focus 4 cyl Front Wheel Drive Automatic 125000 miles

I have 2000 ford focus, recently it has been stalling while driving. I can be driving along and it will start to hesitate, sputter, looses power and when I try to give more throttle it only gets worse, then the engine quits. I put it in neutral pull over, wait a few seconds, and it will restart. It only used to happened once in a great while, but lately it is every day and usually two or more times before I reach my destination.
I replaced the ignition coil, replaced the fuel filter, replaced the spark plugs, replaced plug wires.
My wife was behind me the other day and when I restarted the car, she said that there was a strong fuel smell.
I assumed that meant that the fuel was not burning, so I thought the ignition was not firing. I noticed a small black square piece that is bolted to the ignition mounting plate with one wire coming out of it. I am assuming this is the Ignition transformer capacitor. what exactly does it do? and could this be the problem.

This is a radio noise supressor and not it can not do what your car is doing. Have you cleaned the mass air flow? If not go to your local parts store and buy a can of mass air flow cleaner and pull the mass air flow unit off and clean the inside by spraying it with the cleaner and put it back and see if it fixes it. If not there is a simple test you can do to see if the mass air flow unit is bad. So clean it first and let me know how this works and we will go from there.