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Poor Gas Mileage

2003 GMC Sierra 4.3L V6
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Poor Gas Mileage

Postby Machster69 » Apr 26 2012, 11:39pm

Distributor cap?
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Poor Gas Mileage

Postby Machster69 » Apr 26 2012, 11:41pm

Grab a haynes book for the truck and run through the recommended maintenance schedule
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Re: Poor Gas Mileage

Postby ASTE25 » Apr 27 2012, 12:59am

AC Delco or Standard.
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Re: Poor Gas Mileage

Postby Red Green » Apr 27 2012, 2:11am

" O and the tires I beleive are 275/55/20. "

This may be part of it. My 2004 WT with the 4.3l had 245-75R16 tires. The bigger tires and rims will have some effect on mileage. My truck also had the 36 gallon tank...hate to think of having to fill that now when empty...
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Re: Poor Gas Mileage

Postby Whybenorm » Apr 27 2012, 2:25am

Before you sink any money into anything, you need to actually calculate your mileage. And the gauge on half does not mean 13 gal is gone, see how many gal you put back in when it's on half at fillup. Be a shame to spend money on a bunch of things only to find the numbers said you were getting decent mileage to begin with.
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Re: Poor Gas Mileage

Postby ASTE25 » Apr 27 2012, 2:26am

You can either go back to stock tires or get some lower ratio gears.
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Re: Poor Gas Mileage

Postby #32#32 is online! » Apr 27 2012, 4:24am

Whybenorm wrote:Before you sink any money into anything, you need to actually calculate your mileage. And the gauge on half does not mean 13 gal is gone, see how many gal you put back in when it's on half at fillup. Be a shame to spend money on a bunch of things only to find the numbers said you were getting decent mileage to begin with.

Agree, unless your driving habits never change, and you always fuel up at the same place you may want to average 3 full tanks.
Also, any time my wife drives my truck the fuel economy always takes a big hit.
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Re: Poor Gas Mileage

Postby VORTEC429 » Apr 27 2012, 4:31am

I agree, id try to run atleast 2 tanks of your driving style and calc. The milage from full. If its still bad milage I would do plugs, wires, air filter, synthetic oil and injection cleaner and see what happens. The 20's arnt helping your milage ither.
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Re: Poor Gas Mileage

Postby SilverSurfer » May 03 2012, 5:45am

You can't trust the gas gauge. On an airplane the fuel gauge only has to be correct when it's empty. There's no such requirement on a vehicle. I had one car that dropped like a rock from full to half and took forever to get to empty.

Fill it, reset the trip odo, drive it, fill it again and then divide miles/gallons. The only way to know.
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Poor Gas Mileage

Postby Machster69 » May 03 2012, 1:56pm

Wanna see a crazy fuel gauge

http://www.youtube.com/watch?v=Wq2deTWs ... ata_player

Friend of mines, we are diagnosing it now
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