There is a lot you are not telling us...What condirion were the plugs you removed? I'm thinking you need to do a compression test I don't see the year on this post. That said here are some testing tips,

Answered by merlin2021 (expert)
18,145 answers provided

The car is a 2000. I just had the timing chain replaced, cam seals and valve cover gaskets. The mechanic checked the whole car including compression. Everything was in spec. Spark plug # 4 was fouled before I replaced it. Spark plug #3 was OK.
half the tests you sent me don't apply as I already replaced the coils and plugs.

Response from 14forest
4 questions asked

Ok so the coils have been replaced, what about the plug jackets? If compression is good, these cylinders are on oppsite banks and both at the front position, are we sure the camshaft sensor is set correctly? P.S. Just tryin to help, I am not an Audi specialist! But I did spend quite a bit of time researching for you, if you need more reseach call me! Let me know how things go...good luck. I do like a nice ride myself...

Answered by merlin2021 (expert)
18,145 answers provided

I'm replacing injector #4 tonight.

Response from 14forest
4 questions asked

I replaced the injector. Still same codes. I then swapped ignition modules. Codes went from Cylinder #4 to cylinder #1. I bought a new ignition module and all the codes are now gone. Car runs great. For all you volkswagon and Audi people out there go to virtualvillage.com and look at their Scanmax VAG reader #405. It is a life saver for $149. I bought one.

Response from 14forest
4 questions asked