Manifold/header/muffler/tail Pipe problems of the 2002 Audi A4

I was driving down georgia avenue when all of a sudden my car began to ride very rough, a dash light came on and the engine lost complete power. I was able to start the car up again and luckily was able to coast down hill to my home. (the car is a 5-speed) smoke was coming out of the tail pipe. I called the dealer in rockville and they suggested that it was probably a coil failure. I had just had a coil replaced in February, when a similar type thing happened on connecticut Ave. During rush hour traffic. That time I was able to coast into a gas station. The car died with no previous warning. All four coils have been replaced (4 cylinder) with no reimbursement from Audi because the car is no longer under warranty. I asked the dealer whether this was one of the recall items that Audi put notice out on and they said no. Now that I read that others have had similar problems with their A4s it seems to me like this is a defect in the system and should be covered by Audi. After all, my dealer told me that Audi changed the coil system on the newer models because of the problem.