I have a 1500 HD with a 6.0 L ,I am looking for ideas to improve the mpg'*. thanks for any input.

depends on how much money you want to spend. what size, model, and pressure are your tires? have you done anything like k&n, e3, etc already? what are you getting now?

Biggest effect is your driving habits. Easy foot, coast to a stop sign, etc. Proper tire pressure is also very important. If you have E10 gas and have access to real gas, use that. We get 2 to 4 more MPG on my wifes van.

factory size tires are 245/75/16, I have 285/75/16 on it now. is that going to hurt the fuel mileage? I know driving habits affect mpg'* but I was wondering about a tuner or dual exhaust. I just put in a k&n filter today so i'll see if that helps. I'm not sure what you mean by e3?

E3- New spark plugs that are out.

stock tire size and tire compound and pattern makes the most difference of any other component on the vehicle. tuners are only good if they are meant to increase mileage, most are meant to increase power only. exhaust helps some but not enough to pay for it most times. e3 plugs ive been putting on most all my vehicles lately, they only get slightly better mileage but the way they work they last 2 or 3 times as long as the platinum i was buying. and i have been buying them at advance you can get 20% off so for 4.80 they arent that much more than a good platinum plug and you do them half as often.

you just have a thirsy pig, ive had 2 of those engines in 2500hd work trucks and loaded, unloaded, hwy or average, i always got 11-13mpg. not much you can do unless you spend more money than makes sense to change it. its designed to tow stuff and it does.

The wider tire will effect mileage. More rubber on the road is more friction.

thanks for the input. I appreciate it.