@Eric Dye posted:I have an 03 Duramax and I run the standard filter. The K&Ns let too much air and particles through for normal driving. If you are drag racing and trying to squeek every last bit of HP out of your truck, then K&N might be ok. The HP gains are actually negligable on daily driving applications.
The most important filters on the truck are your fuel filters and water separators. Make sure those are new and change them on schedule. I run extra filtration from a company called FASS. https://www.youtube.com/watch?v=NqfE1eqfTwU
Until recently, the Duramax trucks did not put a lift pump in the fuel tank. The last few years, the GM trucks now have one. The FASS system, in addition to the two extra fuel filters, also included a lift pump at the tank. IMHO, this is important, as it eliminates the need for the CP3/CP4 injector pumps to pull fuel from a fuel tank.
As Eric mentions above, stopping water from reaching the pump/injectors is also very important. The current FASS water filter actually stops water from going forward to the stock filter and injector pump. So, I added one to my truck.
Diesel mechanics constantly state, keeping fuel and air clean is extremely important in modern diesel trucks. In commenting about the OP question, I throw my hat in with the above responses. The stock air filter on your PU is an abundant filter. Just change it often. It is very easy to change, so you don't need to pay for someone else to do it.
One final comment. Since the current Ultra low sulfur fuel has less lubrication than regular No 2 fuel, I now add an fuel additive to be safe (Hot Shot).
Congrats on your new truck, Jason!