2 codes Random Misfires and misfires cylinder 4
 

HAve 2001 audi A6 that I have owned and personally modified (Stage 3 for 70K miles). Great car. Recently have been getting random misfires and cylinder 4 misfires . I have installed ICM delete kit 10K miles ago.Switch coil pacs and still get same codes. Compression is good, in fact some times I get no codes for a while. Why do I get random and cylinder 4 codes. Codes pulled with audi scanner.

How old are your spark plugs? Did you switch them with the coilpacks?

Could also be O2 sensors, IIRC. But that's generally one bank or the other (car runs rich if it can't read the O2).