I've been running a K&N cold air intake on my 04 Yukon Denali for about a month now. The intake noise is very bad so i put the stock intake tube back in a let the cone in place and i swear the truck feels better with the stock tube in place? Am i crazy or is the cold air kit a waste of money?

 

GM did some extensive design work on the intake tube and incorporated the Venturi effect on the intake tube to help air flow from the filter to the TB. Since the tube is not the same diameter from the filter to the TB, the Venturi principle has to be inforced so that the air flow inside the tube is efficient as possible. For all intensive purposes, the stock tube with the cone filter may flow better for your exact application. On the contrary, I have a 2000 model Silverado with the Series 77 K&N, and it flows a lot better than stock. And the intake noise is greater, but I like it that way... If you feel that your truck runs better with the stock tube and cone K&N, then leave it that way. Just chock it up as a learning experience, but your individual results may be just that...individual.