yea its probably just one bad coil. U can get one from ford for like $50 rather than buying the whole set. U should try and wait till u get it to throw a code. When it does the code will be like 806 or sum thin. (6 being the cylinder number). Take that coil and switch it with another cylinder like say cylinder 4. The car should throw a code saying 804. So now u kno u found the bad coil and just replace that one. the coils are infamous for all going with in the same time as one another. I felt like u and didn't wana buy a whole set at the time, so i tried that trick and haven't had a problem yet.... Good luck!