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Old 03-29-2011, 07:37 AM   #1
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Default 1997 GTP lost gas mileage

Before gasohol the car got 27 MPG. When gasohol first came out I used it for a month without realizing it. It was at the end of that month that I noticed my MPG had dropped about 10% to 24 MPG and I began searching out filling stations that sold gas without methanol. I can't be sure that the drop in mileage isn't a coincidence, though.

Also, I now seem to notice a little bit of a flat spot in performance that occurs just before the boost kicks-in. It'* like the boost is coming in late.

I bought the car new and it now has 185,000 miles on it but it still generally runs great and the tail pipes are white.
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Old 03-29-2011, 08:29 AM   #2
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Mike I wish I lived in a state where they didn't blend gas. Once took a trip to Ohio and magically my car wasn't using any fuel and had a ton of power. It was the fuel.

Typically poor fuel economy is caused by the O2 sensor. If you have a scanner available to watch the data of the sensor, you want to see it flipping high to low often. The faster it flips, the better fuel economy will be. If it'* stuck or slow, swap it out.
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Old 03-29-2011, 08:57 AM   #3
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A 10% drop is about right. Remember, your saving gas this way. Or so that is what they tell us.
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Old 03-29-2011, 10:21 PM   #4
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you're saving gasoline..... but burning alcohol in place of it...

so, technically, yes.

i prefer my alcohol in glass bottles and tasty.
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Old 03-29-2011, 10:31 PM   #5
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Default 1997 GTP lost gas mileage

Quote:
Originally Posted by Danthurs View Post
A 10% drop is about right. Remember, your saving gas this way. Or so that is what they tell us.
But I quit using the gasohol and the mileage didn't go back up. So, I figured the ethanol messed up something. I had the injectors cleaned a couple of times. I thought I noticed a difference the first time but only for a week or so. After a while I had it cleaned the second time with no difference.
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Old 03-30-2011, 07:32 AM   #6
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Default 1997 GTP lost gas mileage

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Originally Posted by BillBoost37 View Post
...Typically poor fuel economy is caused by the O2 sensor. If you have a scanner available to watch the data of the sensor, you want to see it flipping high to low often. The faster it flips, the better fuel economy will be. If it'* stuck or slow, swap it out.
What is "often"? 20 times per minute? 2 times per minute?
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Old 03-30-2011, 10:57 AM   #7
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O2 sensor switching speed isn't a very good indicator of fuel economy....

it'* determined by the O2 sensor'* temperature and how quickly the PCM is commanding alternating rich/lean prop steps.
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