04silverado1500

The glass is ALWAYS half full. No exceptions...good way to look at it. Check your plugs and wires + Air filter. Are your tires inflated properly? What brand are they and how much tread life is left?

Sounds good to me. what type of driving did you do to obtain 16.5?

I calculated it and it is about $1000 difference per year so in the long run it does make a difference....so you get 18 mpg in your GM truck or what kind of car do you drive? I have a Pontiac G8 GT. I would do some normal service before getting a tune thats forsure. I also think we need to find out what your gear ratio is! we need this information. I wouldnt be to unhappy with 12 mpg in a truck to be honest. At the end of the day if you bought a truck you shouldnt expect very good mileage. But like a isaid what is your Gear ratio and do some normal Maint on it before you get to busy with trying to tune it. In my old 04 5.3L ext cab truck i avg. about 13 and i could push 18-20 at 60 mph just for your reference.

I'm sorry to step in here but you said you would like to get about 18 mpg or you might have to sell the truck right? You are currently getting near 13 right? if you drive 15k miles a year at 18 mpg with 2.50 gas prices you will spend 2,083.33. If you get 13mpg at 2.50 a gallon of gas you will spend 2,884.61. That is about 800 a year...... the cost of switching trucks or even getting a custom tune or tune up: air filter, new tires (if needed), pugs and wires, Tornado (Hahahaha Jk jk) is going to be quite a bit. Is it really worth it? Is 800 a year in gas worth the changes? furthermore are you even able to increase the mileage that much without changing climate/terrain? I don't know that any tune can give you that much of a mileage increase and even if you could get up to 15 mpg avg., you would only be saving about $385 bucks a year which is most likely to be the more attainable case. So unless you keep the truck a long time the eating the poor mileage is your best bet. But thats just my opinion i get about 18mpg mixed(mostly highway) driving in my car.....Please correct me if i'm wrong on any of the math btw