I thought i read somewhere on the forum about K&N filters not suggested on 4.2.
I cant do a search on K&N so if anyone can please help me out.
thanks!

 

K&N filters are misunderstood and usually get dogged for causing issues with the MAF sensor.

K&N filters need to be oiled occasionally as a method of cleaning. However, if you put too much oil on the filter, it can get sucked into the induction system and gum up the MAF sensor. In short, they are great filters, they last forever and work perfectly fine as long as you don't drown them in an oil bath.

 

They really aren't recommended for any audi engine because the oil from the filter can foul up the MAF sensor element. Personally i think thats horse sh*t because i run a K&N on both my A4 and S4 without any problems. If your worried about the oil messing up the MAF just wash out the oil before installing the filter, but that decreases the velocity of air flow through the air filter. Just don't go oiling the hell out of the filter and such.

 

Oh yeah, I forgot to mention, I had a K&N cone filter on my last B5, granted it's not the 4.2, but it still has a MAF sensor. I had no issues with mine at all.

 

Audi's I've run with a K&N :

99 A4
00 S4
01 S4
04 S4
03 TT
04 S4

I've had zero problems...as others put it, don't over do the oil and you're fine.