that jeep has some very close tolerences when it comes to 02 sensors and
operating parameters and it has 4 o2 sensors those sensor cost 100 each
at least and it' not a cheap throw at it part!gone are the days of100 k
sensors do you wrench at a dealer pete?

Peter wrote:

> ANY vehicle that has over 100,000 miles on it and the mileage drops
> suddenly, it is most likely the O2 sensors that need replacing. They
> are probably still working but not 100% correctly. They don't always
> should up as codes when a diagnostic is run either. You most likely
> have 2 of them, one before and one after the catalytic converter on
> your exhaust. Replace them both.
>
> "philthy" <dbrider@cac.net> wrote in message
> news:46F56C4B.FAC3788A@cac.net...if you are using the
> overhead console for this mileage figures please note that
> only does a average and NOT a real life mileage figure
> if you fill your tank start the jeep the overhead
> recalculates that, by taking a reading off the fuel level
> sensor then it will take a few other imputs including you
> pulling out of the gas station and flooring it it looks at
> the tps speed senor and then recalculates the milage again
> then dispalys the figure giving you the average milage not
> the real milage
> and does it again after you shut it off and restart it
> use the old style of figuing milage and not the overhead and
> if you have bad milage then start looking elsewere
> wilsonb wrote:
>
> > The weirdest thing has happened recently.
> > Grand Cherokee 2000 getting Extremely bad millage @
> > 14.5MPG from
> > 17.5MPG within 1 month.
> > Computer jumps back and fourth with MPG 19.5 then jump
> > down to 13.5
> > then back up to 14.5..
> > and it's noticeably guzzling gas like crazy.
> > (Has 1000,000miles)
> > 4.7lt, 2wd, V8
> >
> > So far have;
> > Replaced all Sparks with E3
> > Cleaned Air filter
> > Put good gas cleaner in tank a few times now.
> > Use regular gas
> > Have take to Chrysler Dealer and they have no clue.
> > (Will call back tomorrow and ask why they didn't do a full
> > Scan on it
> > when I had a 'full' check done on it.)
> > I checked the exhaust and there is a black grid out of it,
> > maybe gas
> > running to rich? Sensors off? Fuel filter?
> >
> > Any else have this or ideas?
> >
> > Thanks so much..
>