So my girlfriend has an Audi a4 (b6?) 2006 i believe 2.0T.
We read the codes and got cyl misfires in Cyl#1 and 4.
I changed the coil packs and it ran fine for about a week before we were right back onto misfiring.
I changed the spark plugs today and it still is misfiring in 1 and 4.

unsure what could be the culprit but it's strange that the coil pack changes allowed it to run fine for a week.
Spark plugs 1 and 4 were a bit fouled compared to the rest.