I just bought an Audi A4 1.8T Quattro and put in a K&N drop in filter into the stock air box. I was riding all over San Diego today enjoying the car.....Then.....The check engine light came on out of no where...my turbo spooled up fine and well really think my K&N filter just messed up my airflow.....has anyone got suggestions about it?

 

Could be a coincidence. You need to pull a code on that check engine light. It could also be that your Mass airflow sensor is dirty. Head over to your local autozone and post up a code so we know what it is, then we can go from there.

 

Is it running lean, or rich? that can indicate a bad reading from the MAF. More then likely it's something unrelated, everything sets off those damn check engine lights, get the codes pulled at autozone and if it doesn't sound important it probably isn't.

 

Yeah well after taking it out and letting it run a little then putting it in again it went off....I know that my Crank Breather Hose was busted and so had it replaced....I need two things but a few people on here have not replied back yet.