2012 gt 135 miles in shop

I picked up my 12 GT convert,drove it for 6 days had 135 miles on the car.When i thought i was going to have to walk home.It seemed like it was running on 4 cylinders the cel was flashing like a xmas tree.took it to the dealer the next day,it ran prefect. No cel code.they test drove and it did it again.after the dealer talk to ford they changed all fuel injectors.I picked up the car and two hours later it did it again,the cel light stayed on.The next morning i went to the dealer and it ran perfect,but it did have a cel code (misfire on cylinder #2) that was Saturday . I now have around 250 miles on my car,a different mechanic is going to check it out Monday 9-26-11.
To say the least I'm car sick.Does anyone have an idea.

I m not sure, they called the ford hot line and thought it was one injector.ford said to move the original injectors to the other side and see if the problem followed,it did. to be sure ford said to replace all injectors.

It throw the same cel code after the new injectors were installed,ford had them move cylinder 2 ignition coil and spark plug to the other side.ford wants to see if it throws the same code again.this all happened with less than 200 miles,now I'm crowding 500 .the car is running perfect,I will drive until it breakes or throws a code.