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Huge Sudden drop in gas mileage SOLVED

Old 07-08-2011, 07:30 AM
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Default Huge Sudden drop in gas mileage SOLVED

I think it is just as important to post solutions as it is problems. I recently had a massive drop in mileage for what seemed like no reason. I went from 22 mpg in my Cherokee to 10 mpg in ONE fill up. I had no idea why. It ran fine. I found several other posts which described the same problem and nobody had a solution, everyone just said "plugs, wires...." or something about winter fuel where people would say they lose 2-3 mpg in the winter. That does not explain a greater than 50% drop in MPG.

My problem was ethanol gas, of course. Filled up with non ethanol and it has worked fine. Also, the bad gas came from a discount gas station. No more -- only brand name fuel like Shell or BP for me.

Hopefully someone will find this helpful when they type sudden drop in mpg into google.
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Old 07-08-2011, 11:39 AM
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A 50% drop in MPG just because of Ethanol? Sounds far fetched but I always did think ethanol was just a scam by Big Oil to sell more gas by reducing your mileage.
Old 07-08-2011, 11:50 AM
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Originally Posted by 95Cherokee
A 50% drop in MPG just because of Ethanol? Sounds far fetched but I always did think ethanol was just a scam by Big Oil to sell more gas by reducing your mileage.
Ethanol is a scam from the EPA. BIG OIL wanted and wants NOTHING to do with it cause it cuts into their profits. Ethanol is also 15% less efficient and cost much more to refine than Gas. OH before you go blaming BIG OIL for high gas prices and excess profits. Consider who really make the most money off of FUEL. BIG OIL makes about $0.10 per gallon sold, the US government makes more then $0.50 per gallon.
Old 07-08-2011, 11:53 AM
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I have a hard time believing Big Oil only makes 10 cents off a gallon of gas that is about $3.50/gal.

Anyway, I knew SOMEONE was scamming us with the Ethanol.

Last edited by 95Cherokee; 07-08-2011 at 11:56 AM.
Old 07-08-2011, 12:00 PM
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22 MPG?? I don't think I even got that when I was stock.
Old 07-08-2011, 12:04 PM
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lets see you are paying $3.50 at the pump. 50 cents of that is a direct fuel tax to the FED that you pay for the privelage of driving, my state charges an additional 18 cents, and the gas station get 5-7 cents, some cities and counties hit it also, imported oil gets taxed when it gets here. Then there are the other State and FEDeral taxes. Oil is taxed while it is in the ground then again when it is pumped out, again when it is refined, again when it is sold to the reatailer then again at the pump. Politicians LOVE high gas prices, the more it costs the more the Government gets. The US government is afterall the BIGGEST oil speculator out there.
Old 07-08-2011, 12:33 PM
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I just traveled from NY to Las Vegas -arrived yesterday. Took my minivan BUT in many states I was filling up and wasn't paying attention and filled up with 85 octane with NO ETHENOL. I was surprized since I never saw anything less than 87 octane and nothing WITHOUT the ETH added. Either way the Van ran great and got much better milage on the straight 85 than other states with the blend. Friggin scam.
Old 07-08-2011, 12:38 PM
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I have the same problem. I wish i could find a gas station with regular gas every thing is 10% around here
Old 07-08-2011, 12:51 PM
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Ethanol sucks! Its hard on rubber parts, absorbs moisture, and causes the fuel to go stale quickly. If you're using it in a 2-stroke like a chainsaw or weedwacker, try and use your mix in less than 6 weeks.

The Gov't is subsidizing ethanol production, so in addition to the tax you're paying on the fuel, you're paying additional for the subsidy in the form of income tax. Don't forget that using corn based ethanol is also causing food prices to rise....and all of this in addition to less fuel mileage!
Old 07-08-2011, 12:54 PM
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Originally Posted by fatboyadams
I have the same problem. I wish i could find a gas station with regular gas every thing is 10% around here

Most, but not all, Shell stations sell straight gas. Check Shell stations around your neighborhood.
Old 07-08-2011, 01:31 PM
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Default Shell 10% Eth

Unfortunately, Shell in my part of central TX has started selling 10% Eth gas.

The sale of this stuff also partly depends on the clean air rating for a metro area.

BTW, Hi! This is my first post here. I bought my 96 Cherokee SE 2 weeks ago and have fallen firmly in love with it. At 96k miles, I plan to be driving this gem a loooong time.
Old 07-08-2011, 03:21 PM
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Originally Posted by tx96
Unfortunately, Shell in my part of central TX has started selling 10% Eth gas.

The sale of this stuff also partly depends on the clean air rating for a metro area.

BTW, Hi! This is my first post here. I bought my 96 Cherokee SE 2 weeks ago and have fallen firmly in love with it. At 96k miles, I plan to be driving this gem a loooong time.
Welcome to Jeepin' and the Forum!
Old 07-08-2011, 03:35 PM
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Ethanol is a type of alcohol and therefore burns hotter than gasoline causing a rise in cylinder tempatures. Most ECUs will see the temp increase and interprit this as a lean condition and richen the fuel mixture to help lower the cylinder temperature.
Old 07-08-2011, 03:49 PM
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Originally Posted by Outlaw Star
Ethanol is a type of alcohol and therefore burns hotter than gasoline causing a rise in cylinder tempatures. Most ECUs will see the temp increase and interprit this as a lean condition and richen the fuel mixture to help lower the cylinder temperature.
Which therefore leads to burning more fuel and increasing emissions. Burning more fuel also increases our dependence on foreign oil.

Where is the savings?

Last edited by Firestorm500; 07-10-2011 at 12:13 AM.
Old 07-08-2011, 03:54 PM
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Bingo!

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