I have a 2010 sierra 2500hd 6.0. will putting a cold air intake system help my fuel mileage? If so what do you recommend?

A CAI by it'* self wont help mileage, unless you have a dirty filter now and go to a new clean one.

no it is a clean one..just trying to increase my fuel mileage

A CAI wont help that. A good tune up, new plugs, new wires, clean air filter, tires up to correct pressure, new O2 sensor if you don't know how old it is. Clean the MAF, clean the throttle body.

If you breathe through a paper towel tube instead of a straw, your body still uses the same amount of oxygen. Same principle here.

If you prefer horsepower to fuel mileage, then I'd recommend intake work as a first step forward; however, if you're trying to save a couple bucks, invest in a full tune-up instead.

And welcome to GM Forum! Stick around; we'll keep that Sierra running long after the dealer says "who are you again?"

truck is a 2010 i would hope it doesnt already need a tune up and O2 sensor