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Old 12-06-2017, 03:34 PM   #1
bluec10
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Question Poor Fuel Economy - Advice?

Need some advice - I'm getting an average of 13 mpg out of my 2005 GMC Sierra 4x4 with a 4.8L. Truck has 156,000 miles on it. I live in Canada so it's winter right now but the mileage seems pretty low.

Any advice about what helps improve mileage in these trucks? Is this the kind of mileage that others are getting?
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Present:
'14 Honda CRV - Great daily driver. Just works.
'05 Sierra SLE 4x4 - "Dad can I take the truck?"
'69 GMC 32,000 - fix, drive, relax, fix...
'79 Honda GL 1000 - retro touring at its best.

Past:
'94 F-150 from the "F word" company. I'll admit it...good truck. Sold what was left of it for $800 to a guy who came to pick it up at 11:00 PM with cash in hand. Hmm.
'79 Sierra Grande (Black) organ donor - perfect rebuildable 4-bolt 350 and a good TH350.
'76 Sierra Grande (Orange) - hate isn't too strong a word. Kid who bought it turned it into a hot rod.
'68 C-10 R.I.P. - Dad's old truck...too far gone to resurrect.
'59 C-50 - with hoist. Truck is gone, wife isn't. Nuff said.
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Old 12-06-2017, 05:57 PM   #2
GASoline71
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Re: Poor Fuel Economy - Advice?

I'd say you're as close to the best you can get now. My '06 K2500 Silverado gets maybe 12mpg downhill with the wind at my back and I have a 6.0L. A heavy 4x4 with a 4.8L has to work a bit.

Gary
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Old 12-07-2017, 11:46 AM   #3
BR3W CITY
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Re: Poor Fuel Economy - Advice?

My Yukon weighs about 6700 lbs, and with the 5.3 I get around 15-16, but can do a bit better. I've got pretty low rear gears, so my worst mpg is the 10-35mph stop n go stuff. 40+ cruising and it improves drastically.

The stock intake and exhaust system is pretty restrictive, so there are mpg and power gains available there (but the cost doesn't always offset the mpg difference).
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Old 12-08-2017, 02:54 PM   #4
68Gold/white
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Re: Poor Fuel Economy - Advice?

You need to find someone that can alter the factory tune settings. I talked to my buddy's son about one of the programmers for a friends pickup. He said he didn't think much of them, a proper tune would likely yield better results, especially for the $$$. Diablo Motorsports was the name of the programmer I believe. My buddies 2008 5.3 4 door 2WD gets 17 MPG, he was hoping for better. He has not yet done anything.....
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Old 12-10-2017, 02:17 PM   #5
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Re: Poor Fuel Economy - Advice?

I live in Canada my 2005 GMc with a 6.0 eats gas in winter 24 to 100liters all the time
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