After only 1k miles after purchase my Check Engine light as come on.

P0440 and one other (left the paper at work)

I haven't overfilled on Gas, the Gas Cap is completely on (2 clicks), and I haven't OVERLY pushed the car either haha.

The only update was replacing the STOCK filter with K&N Drop In Filter. Before I go to the dealer, any advice on what could cause this or if a quick fix is known?

 

Clear the code and see if it comes back. It may not.

 

it would help if you included a year and engine model... since you only have 1000 miles on it, I'm assuming it's a 2016 model?

regardless, you're on the right track to just take it into the dealer. it's covered by warranty; might as well