I have a 2001 A6 w/a 4.2L (50k miles)

I get the following codes:

multiple misfire
misfire cyl 5
misfire cyl 6
misfire cyl 7
misfire cyl 8

Also an oxygen sensor range error from the same bank. Probably a result of the misfire. It's Not likely all the coil packs died at the same time so I though it was a cam position sensor. I replaced the cam position sensor but haven't had any change. I know ignition control modules are a problem on a lot of Audis but the 4.2 does not have one.

Any other suggestions?

Thanks!