Help on flashing check engine light.
 

I have an 06 Audi A4, 2.0T and I had my coils replaced about 6 months ago by what I view as an unfit mechanic but I just got P0301 again on my car. It seems to shift fine under about 2500 rpm but if you need to give it more gas, it struggles to shift and a couple of times the check engine light has been blinking. Does cold weather affect the coils? Is there any way it was a fluke and I can still drive with it, or should I just replace the first coil? Should I replace all of them again? I am ready to get rid of the car cause this stuff seems to happen a lot. Any help would be greatly appreciated...