Reply With QuoteSounds like a sensor or ignition. May need a tune up or at least new plugs.
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Corvette: gas mileage
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- 07-02 06:02 PM #1ssomeGuest
gas mileage
a few weeks ago i posted a note about my '86, 26K miles, dropping in the
indicated ave gas mileage from 17 to 13 around town. topped up the trans
fluid, changed the air filter - no luck.
i had been driving easy around town not trying to draw attn. then i got
out on the freeway and the mileage shot back up to 25 in overdrive which was
about what it was in the past. it dropped to 20 ave when more in-town
driving was done.
then i started it up the next day and around town it was registering 3.6
mile per gal ave. got out on the freeway and it went back up to 25.
bad computer function? next day it continued at about 20 with some
freeway/town driving.
ssome
Mystery Book Trader
http://home.comcast.net/~sssome/
- 07-02 08:13 PM #2piperjimbGuest
Re: gas mileage
- 07-02 10:17 PM #3DadGuest
Re: gas mileage
What did you expect, 4 or 5 MPG increase?
was
Funny how that works.
If you're reading the instant mileage I would say that's about right. Do you
think maybe the computer puts out a signal for a rich mixture when you start
it up? If you haven't read these before on a regular basis how do you know
what is good, bad, or indifferent? I think you're getting to sensitive to
the gas prices, get a Honda, they get better mileage sometimes.
--
Dad
98 C5 Black/Black/Auto
72 Shark Black/Black/4spd
- 07-03 03:25 AM #4ssomeGuest
Re: gas mileage
put in platinum plugs in the beginning
ssome
"piperjimb" <com> wrote in message
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plugs.
- 07-03 07:16 PM #5ssomeGuest
Re: gas mileage
Today, Thurs, each time i started it up the ave mileage was fixed at 9.9 for
about 5 miles then it snapped back to the low 20's. has anyone seen this
behavoir before?
"piperjimb" <com> wrote in message
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plugs.
- 07-03 08:49 PM #6DadGuest
Re: gas mileage
Yes, it reads at a set time interval, not every millisecond, don't know what
the value is but it's normal. Set it to average mileage instead of instant,
and it won't do that, unless you reset it every whip stitch.
--
Dad
98 C5 Black/Black/Auto
72 Shark Black/Black/4spd
"ssome" <net> wrote in message
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for
- 07-03 10:37 PM #7ssomeGuest
Re: gas mileage
'86 , 26K miles
i have it on Average, and leave it alone.
just is strange behavoir compared to past years.
thanks,
ssome
"Dad" <net> wrote in message
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what
instant,
this
- 07-04 12:49 AM #8Vette88Guest
Re: gas mileage
It really sounds like you are looking at the INSTANT MPG rather than
AVERAGE -- switch setting check should confirm.
However, the one way to check is to drive for a while and calculate your MPG
based on next fill and compare - your calculations vs Avg readout.
Assuming you've got the switch on AVG not INSTANT I'd guess the on-board
computer is wacked or the sensor !
"ssome" <net> wrote in message
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was
- 08-10 01:03 AM #9PACalesGuest
Re: gas mileage
Sounds like your ECM is going bad, I had to replaced the ECM on my 89 Vette
for the same problem.
Phil
"ssome" <net> wrote in message
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was
- 08-12 06:19 PM #10greybeardGuest
Re: gas mileage
I also had to replace the ECM on my 89. Exactly the same
symtoms ... then it got worse - fuel use and fuel remaining
would zero out and the idle would jump to 1500 RPM stopped
in Drive Range, farting & bucking of and on again as the
display switched back and forth.
Have your ECM checked with a scanner - turns out my data
transfer was cuting in and out, and never going into a
proper "closed loop" operation.
Easier and cheaper to fix while it's "still" running.
Good luck.
PACales wrote:
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