MPG LOSS! Please Help
Thread Starter
Heel & Toe
Joined: Feb 2002
Posts: 15
Likes: 0
From: Tacoma wa
MPG LOSS! Please Help
Changed the optispark,plugs,coil,airfilter,wires,and oil 2 weeks ago. The car needed a serious tuneup, I was averaging 18 mpg over a 1 year period of time, since then I am getting about 15.5mpg its not a huge deal but I wanted to know what the possible causes would be.
Thanks
:cheers:
Thanks
:cheers:
Racer
Joined: Mar 2001
Posts: 280
Likes: 0
From: Honolulu Hawaii
Re: MPG LOSS! Please Help (vettehead1995)
You must have changed your driving habits. More City and less highway driving. Or maybe your foot got heavier on the pedal. I get about 15mpg with City and Highway driving.
-Tim
[Modified by Hawaii89vette, 11:20 AM 2/27/2002]
-Tim
[Modified by Hawaii89vette, 11:20 AM 2/27/2002]
Drifting
Joined: Jun 1999
Posts: 1,438
Likes: 0
From: Bowie MD
Re: MPG LOSS! Please Help (vettehead1995)
Possible causes:
1. your right foot got 25lbs heavier in the past two weeks. :D
2. (more likely) O2 sensor potentially going bad. Mine were bollixed up and my mileage took a nose dive.
1. your right foot got 25lbs heavier in the past two weeks. :D
2. (more likely) O2 sensor potentially going bad. Mine were bollixed up and my mileage took a nose dive.
Le Mans Master
Joined: Jun 1999
Posts: 6,272
Likes: 2
From: Chino Valley AZ
Cruise-In I Veteran
Cruise-In II Veteran
Currently Corvette-less
Re: MPG LOSS! Please Help (85vetteguy)
OK, I take a totally different read on your question ~~~
It looks as though you don't reset your average MPG each time you get a new tank of gas. Therefore, the average MPG that you see is a composite of highway and city driving. If you have not taken any long trips since the rebuild, then your average is going to reflect city driving only.
Try this:
Go out on the highway (Interstate/Freeway) and set cruise control at 70 MPH on level ground. Reset the average MPG and see if the new reading is somewhere between 25 and 30 MPG. If so, then you are doing OK.
:seeya Purp
It looks as though you don't reset your average MPG each time you get a new tank of gas. Therefore, the average MPG that you see is a composite of highway and city driving. If you have not taken any long trips since the rebuild, then your average is going to reflect city driving only.
Try this:
Go out on the highway (Interstate/Freeway) and set cruise control at 70 MPH on level ground. Reset the average MPG and see if the new reading is somewhere between 25 and 30 MPG. If so, then you are doing OK.
:seeya Purp
Race Director
Joined: Sep 2001
Posts: 14,687
Likes: 753
From: NEwhere Ohio
When my O2 sensor went out my MPG went down from 18 to 14.5
When my O2 sensor went out my MPG went down from 18.something to 14.5.
My car ran so rich my plugs fouled, and the exhaust smelled of gas.
Also, my check engine light never came on.......
My car ran so rich my plugs fouled, and the exhaust smelled of gas.
Also, my check engine light never came on.......
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: When my O2 sensor went out my MPG went down from 18 to 14.5 (vettehead1995)
Which O2 sensor, I believe there are 3, or do you change them all
Drifting
Joined: Jun 1999
Posts: 1,438
Likes: 0
From: Bowie MD
Re: When my O2 sensor went out my MPG went down from 18 to 14.5 (Vette92)
Yep, what he said. I only changed out the forward two sensors (My 96 has 4 of them) and my mileage went right back up.
In order to remove them without dropping the exhaut you will need the appropriate sized crows foot and an extension long enough to reach up there.
I could get to the drivers side one with a shorty wrench but not the passenger side without the crows foot.
In order to remove them without dropping the exhaut you will need the appropriate sized crows foot and an extension long enough to reach up there.
I could get to the drivers side one with a shorty wrench but not the passenger side without the crows foot.
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Re: When my O2 sensor went out my MPG went down from 18 to 14.5 (MCPOWHITE96)
I'm suffering the same problem too. Except that I did change both of my O2 sensors and still no difference. Now what? I installed the Bosch ones from my local AZ. :seeya
