My car is shaking like is has epilepsy on and off. I will go for a couple of miles with it driving smooth, then it will start shaking like crazy, then go back to normal. I took it to Ford and was charged $120 to tell me I need an entire new fuel injection system. I called to some mechanics, and they said it sounded like one injector may be clogged. I got some injector cleaner run directly through the engine, and that didn't help. Should I do that more than once? Somenoe mentioned about manually getting the injector cleaned. How much does that ususally cost?

Any ideas or suggestions would help. My last resort it getting rid of the stupid thing.