RacerX

I got a 1993 and it has a 30 gallon tank.

jvc350

I have a 2010 5.3 4x4 crew cab with a six speed and I average 17.5 per gallon.

You have to keep your foot out of it to get the 17-18 avg. Whenever I drive 75 or better the mileage goes down.

jayvas

Wow - it sounds like we have the exact same truck (2011 5.3L, Active Fuel Managemnet) and I too have tried to get anywhere near the mileage on the sticker with no luck. I see the active fuel management telling me I should be getting 28 MPG or better on the highway (you can watch this change constantly on the DIC) but on the PA turnpike with cruis control set to 65MPH (which was very difficult to stay this slow) for 4 hours the best I got was 16.1 MPG. I constantly drive in such a way to get best MPG (slow starting, minimal stopping, 2-Hi, etc) and my truck is only averaging 14.1 MPG. It drives me crazy - I almost bought the Tundra but the Silverados MPG was the selling point. I have an appointment to bring my truck in next Monday because a retired GM Mechanic told me something has to be wrong.

RacerX

There is nothing wrong with your truck. In Central PA they have hills and mountains everywhere. You want 28mpg? You will have to move to Missouri or Kansas. All flat. Take a trip out west and then do the same test in Montana or Nebraska AT 55MPH with 15-16" wheels. I bet you get closer to specs than you ever will in Pennsylvania. Plus no one likes driving at 55.

catsrg8

I have a 2011 crew cab 1500 with 5.3L engine. 900 miles so far. Getting 16-17 mostly in town. Haven't been on interstate to test highway miles. Usually in v8 unless going down an include then shows v4. Has 3.42 gears and 18" tires. What do you have? Do you have a bed topper? Any other exterior mods. Visor, bug shield etc, they take mileage away. I have no visor, no bug shield and a bed topper.

jayvas

I have the 5.3L V8 with Active fuel management - no bug shield, sun visor, etc. It did come with the 18" aluminum wheels. I always put Exxon regular 89 in it - per manual (top tier, 89 octane). Active fuel management goes to V4 very often (coasting, long straight away, down hill, etc). Dealer said maybe it has something to do with break in period but I now have 5400 miles on it and no changes. I already had dealer change oil and rotate tires. I slow down way on advance of lights or traffic so I don't have to stop, I very slowly accelerate and no matter what, I only get 14 - 15 MPG around town and the most 16-16.5 on the highway.

country_09

if you're thinkin the AFM is what's gonna get you ga mileage..your wrong. it will only stay on if your truck is on straigh flat level ground, one little hill and boom back to v8 mode. so the best mods you can do to get some gas mileage is a free flow exhaust(magnaflow, dynomax, glasspacks, etc) k&n filter and a blackbear, Wheatley, or Nelson tune. once those are in you should see bout 2-3 mpg back. I went from 12 to 15.5 in my 01 with 33x12.5x20s that I put on after these mods.

Hunt4X4

i would go first with a tune up. air intake and exhaust mods are a waste if you are getting them for the reason of improving mpg. now they are great for horsepower, but don't throw your change out the window if you are simply wanting to improve mpg. when my buddy and i both got exhaust and air intakes for this reason, and to sound good, i had no mpg improvement and he only had about .2 mpg improvement. so start with a tune. also tires change a lot, but chevy comes stock with tires small enough to get the mpg they put on the window

jayvas

I looked up the exhaust modification and the tune packages mentioned and maybe down the road I might change those but I don't want to do anything right now that may mess with warranty. I don't think a tune up on a brand new truck would do anything but I bet the tires would help - my truck came with an upgraded tire and rims - 18" aluminum and the tires are more of an off-road type tire which I'm sure hurts the fuel economy. Isn't worth spending the money now on the tires though.

ravinforone

I had a 94 Safari and GM said I would get 26 mpg, and I got it. I had a 2003 Serria and it was rated for 26 mpg, and I got it. Silverado 5.3 liter rated 20 city 30 highway, well the best I have gotten is 23 mpg. Now I am in Ontario so are gallons are larger then the gallons in the USA but 23 mpg is no where near what I paid an extre 3 grand for.