I go to the job last week and the car have suddenly bad performance. when I put in the neutral the car have a bad noise in the silencer. I change the FOUR coil pac and the car ON THE IDLE are OK. but when I push it a little bit, I detected other misfire on the cylinder 2 and 4 on VAG-COM. I inverse the coil for a test. now the misfire are on the 1-2-3-4 cylinder. I DON'T CHANGE the spark plug but it is very special that inverse the coil pac and the misfire are on all cylinder. what's wrong????

please help me!!

thx!