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Poor poor gas mileage

Poor poor gas mileage

Postby flyenfloyd [OP] » May 15 2018, 12:32am

I have a 2004 chevy silverado 2500 HD 6.0 with 330,000 miles. Runs fantastic, looks like new. Take really good care of it. Recently my gas mileage has plummeted from 11.5 to (8.5) and with gas at $4.00 a gal in calif. Its killing me. Plugs are not bad, breaks are not binding, running 100% synthetic. Tranny flushed every 35,000 .
Only thing I haven't done and thinking might be the culprit is fuel injectors. Never done. Any intelligent advice welcomed. Thanks again
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Re: Poor poor gas mileage

Postby Zrock » May 15 2018, 12:52am

First things I would do is plugs, wires, fuel filter and clean the throttle body especially the idle passages as well as mass air flow sensor. Unless the plugs and wires have been done recently just because they look good does not mean they are performing. I usually do plugs every 1-2 years and wires every 3-4

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Re: Poor poor gas mileage

Postby 19trax9519trax95 is online! » May 15 2018, 1:33am

O2 sensors ever been changed?
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Re: Poor poor gas mileage

Postby tsduke » May 15 2018, 1:33am

Move??
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Re: Poor poor gas mileage

Postby CT2500HD » May 15 2018, 1:47am

Plugged catalytic converter will result it horrible MPG. You would get a distinct "plugged" sound to the exhaust and/or rattling as the ceramic insides break up. In severe cases, your exhaust manifolds will also literally glow a dull red-hot as gases are backed-up and have no where to get rid of the heat. Given you have 300K+, this is a distinct possibility.
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Re: Poor poor gas mileage

Postby rollover » May 15 2018, 6:17pm

Do you have a check engine light on and if so what are the stored codes?
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Re: Poor poor gas mileage

Postby adam86107adam86107 is online! » May 15 2018, 6:50pm

So I was curious what you would be spending on fuel assuming you put all those miles on that truck. Here is what I come up with:

330000/14 = 23,571 miles driven annually

23,571/x = 8.5mpg

23,571/8.5 = 2,773 gallons of fuel used annually

2,773*4 = $11,092 annual cost of fuel

Is that correct? If my math is correct that is ridiculous. I may have missed something somewhere in my calculations though.
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Re: Poor poor gas mileage

Postby Jasen » May 15 2018, 11:38pm

When as the last time you changed the air filter.
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