Decrease in gas mileage...cause?
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Joined: Oct 2002
Posts: 52
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From: Colorado Springs CO
Decrease in gas mileage...cause?
Hi all,
I have a 95 LT1 auto, and it seems lately my gas mileage has dropped pretty significantly... from 19-20 city average to low 15's. I think I read somewhere that it might be because of bad Oxygen Sensors.. Anyone have a clue? I have not changed my driving style at all. The car has 43K miles. :confused:
I have a 95 LT1 auto, and it seems lately my gas mileage has dropped pretty significantly... from 19-20 city average to low 15's. I think I read somewhere that it might be because of bad Oxygen Sensors.. Anyone have a clue? I have not changed my driving style at all. The car has 43K miles. :confused:
Race Director
Joined: May 2001
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Re: Decrease in gas mileage...cause? (journeyman)
That's always a good place to look. Another option might be your thermostat! I know that sounds kinda stupuid but it's possible. My brother had a 99Z-28 that basically didn't have a thermostat in it. We replaced it and not only does he now have a heater, he's getting much better gas mileage.
As it turns out the car was running so cold that it would never enter closed loop, costing him serious gas mileage. He's getting about 50 more miles on a tank.
As it turns out the car was running so cold that it would never enter closed loop, costing him serious gas mileage. He's getting about 50 more miles on a tank.
Instructor
Joined: Apr 2001
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From: Uledi, PA
Re: Decrease in gas mileage...cause? (journeyman)
Hey Journeyman, I know what you mean. Seems like mine has dropped off some too but I can't tell if it's the car or me mashing the pedal to listen to the Corsa's. :lol:
Burning Brakes
Joined: Jul 2003
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From: Nashville TN
Re: Decrease in gas mileage...cause? (journeyman)
I am having the same problem with my GS, 15 mpg is just about max for me around town since I changed from my stock exhaust to my longtubes, O2 sims, x pipe, and the B&B's just 2 months ago. I guess I'll start my search from there
Team Owner
Joined: Sep 2001
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From: Athens AL
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Re: Decrease in gas mileage...cause? (journeyman)
Almost always, a big drop in mpg is due to one or more bad O2's :yesnod:
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From: HEMET California
Re: Decrease in gas mileage...cause? (Amazing1)
Ok, I'll ask. Where are the o2 sensors and what is the best way to test to determine if they need to be replaced, or the filter is dirty, etc? :lurk:
Team Owner
Joined: Sep 2001
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From: Athens AL
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Re: Decrease in gas mileage...cause? (Amazing1)
Ok, I'll ask. Where are the o2 sensors and what is the best way to test to determine if they need to be replaced, or the filter is dirty, etc?
The O2s, technically you need to check their voltage readings with a tester or some type of scanner. They should read only in a certain range, and youll be able to tell whether or not its staying in open loop from that. There is only one O2 on L98s, stuck into the Ypipe in front of the precats. There is one on each side in the early LTs, then later ones have an extra one or 2.
