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Typical Gas Mileage for a 2005 1500 5.3l?

onecrazyfoo4u

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onecrazyfoo4u Enthusiast

onecrazyfoo4u

Posted
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I have an 05 1500 with the 5.3l motor, auto transmission, crew cab, and 4x4. I know the original tag showed highway mileage of 20mpg. The best I've been able to squeeze out of it is 17mpg on 100% highway...but I'm usually at 15-16mpg with some mixed driving. I calculate by hand from tank to tank...not concerned with what the mileage computer shows me. I drive with a soft foot, and very rarely to I hit the gas hard.

 

What does everyone else get? My buddy has an identical truck as mine, just a 2006 instead and regularly gets 18-19mpg on the highway. My truck just passed 140k miles...but has all new fluids (front/rear diff, transfer case, transmission, synthetic oil). Has a new air filter. Everything on the engine, transmission, exhaust is stock. Stock wheel and tire sizes, no lift kits at all. Just had the knock sensors replaced since they were throwing codes. Throttle body and intake was all cleaned out too.

 

What else could I change out to get better mpg? Maybe the spark plugs and wires? What about O2 sensors? What about any sensors? Would high flow catalytic convertors help? I don't have any engine codes, but want to get better mileage if possible. Thanks for any help.

jaslo Enthusiast

jaslo

Posted
Posted

Did you put a heavier tire on recently? These trucks came with P-rated tires, anything with a LT rating will decrease gas mileage slightly.

finn5033 Enthusiast

finn5033

Posted
Posted

What gears do you have? My truck at the moment is just a weekend vehicle so it is a pretty even mix of highway and town driving. I have 4.10 gears and over the last year I'm at 16.5mpg average.

onecrazyfoo4u Enthusiast

onecrazyfoo4u

Posted
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The tires are original size, not sure what the load rating is though. I bought the truck last year and haven't changed tires or anything.

 

I don't know what gears it has...how do I check? Can you check with the VIN number or by looking?

finn5033 Enthusiast

finn5033

Posted
Posted

open your glove box and there will be a sticker with a bunch of RPO codes on it. Look for codes that start with G, there should only be 1 or 2. Go to the home page of this site and click on the tools tab, there will be an RPO code look up. You can type the code in there and find out what gears you have.

finn5033 Enthusiast

finn5033

Posted
Posted

It depends of course on what you are trying to tow. But IMO that is a good compromise for both. Decent towing gear and good for mileage.

fondupot Senior Enthusiast

fondupot

Posted
Posted

Sweet thanks, I have GU6 and G80...looks like a 3.42 rear axle ratio. Is that good or bad for mileage or towing?

 

3.42 in that year of truck was better for mileage, but with the 4 speed transmissions it didn't help that much.

 

Typically 3.73, and 4.10 was for towing back then with the 4 speed transmissions.

 

Also according to this website: https://www.fueleconomy.gov/feg/bymodel/2005_Chevrolet_Silverado.shtml

 

There aren't any 4x4 trucks from 2005 that were rated at 20 mpg highway. The only one that has a 20mpg highway rating is a 2wd, 4.3L V6

The best rated 5.3L v8 4x4 is the hybrid at 18mpg. So your 5.3L 4x4 is likely rated around 15 city 17 highway.

 

I had a 2002 Silverado 4x4 5.3, 4spd. with 3.73 gears. Before lift and tires, I got about 14 around town and 17 highway. Your 2005 isn't all that different from that 2002. So I would say 17mpg highway is about as best you will get.

onecrazyfoo4u Enthusiast

onecrazyfoo4u

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3.42 in that year of truck was better for mileage, but with the 4 speed transmissions it didn't help that much.

 

Typically 3.73, and 4.10 was for towing back then with the 4 speed transmissions.

 

Also according to this website: https://www.fueleconomy.gov/feg/bymodel/2005_Chevrolet_Silverado.shtml

 

There aren't any 4x4 trucks from 2005 that were rated at 20 mpg highway. The only one that has a 20mpg highway rating is a 2wd, 4.3L V6

The best rated 5.3L v8 4x4 is the hybrid at 18mpg. So your 5.3L 4x4 is likely rated around 15 city 17 highway.

 

I had a 2002 Silverado 4x4 5.3, 4spd. with 3.73 gears. Before lift and tires, I got about 14 around town and 17 highway. Your 2005 isn't all that different from that 2002. So I would say 17mpg highway is about as best you will get.

 

Okay, appreciate the help. Not sure where I got the 20 mpg number from. Guess I won't worry too much about mileage then. My buddy must have a unicorn of a truck to get nearly 20mpg that often!

fondupot Senior Enthusiast

fondupot

Posted
Posted

 

Okay, appreciate the help. Not sure where I got the 20 mpg number from. Guess I won't worry too much about mileage then. My buddy must have a unicorn of a truck to get nearly 20mpg that often!

 

There are things you can do to help get better mileage. You can get a custom tune. I remember after getting a custom tune, I could see 18-19 mpg highway with my 2002. And even after my lift and tires I could still see 17-17.5 on the highway. Pretty good!

 

Also, I think around 05-06 they started using electric fans for the radiator, see if you truck has a regular engine driven fan, or e-fans. There are kits you can buy to convert to e-fans. That will help reduce parasitic drag on your motor to increase all around mileage. I never got around to doing e-fans, but I know it was a popular mod.

 

Also, intake and exhaust would help a little. But I would definitely pair those with a custom tune.

 

I'm sure there are others, but those two I remember were big help for mpg.

onecrazyfoo4u Enthusiast

onecrazyfoo4u

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Okay sweet. Both of my fans are already electric, so good to go there. My buddy does have a plug in tuner...no other mods though. So maybe that's giving him a couple mpg boost when cruising on the highway. I'll have to ask him what his tuner is.

intheburbs Enthusiast

intheburbs

Posted
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I'd say you're doing pretty good with your current mileage. My '01 Burb with the 5.3 and 4.10 gears got, at best, 15-16 MPG on the highway.

Daryl LBZ Senior Enthusiast

Daryl LBZ

Posted
Posted

That seems to be pretty good. I have 3.42's and since I've been making longer trips I'm up to 15 mpg and still climbing. I also have 6 ply LT series tires.

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