S70 100k maintenance?

My '98 S70 is about 106k miles now. A mechanic friend told me all it
needed for 100k maintenance were things like oil/filter change, fuel
filter change, transmission fluid change, and new spark plugs (all
done).

However, I'm wondering if I missed anything like engine timing
adjustment or any type of adjustments?

I ask because over the last 8 months my gas mileage has been dropping
from 23MPG to 19MPG (87 gas always used) without change of driving
conditions or habits. Such drop also conincided with the time when then
odo reached 100k.

Adding of fuel injector cleaner didn't help.

What should I do to bring the gas mileage back?

Thanks!

 

First make sure the wheels rotate freely after driving the car to make
sure the brakes aren't hanging up. When spinning the fronts, don't
mistake resistance from the differential for dragging brakes.

They're not regular maintenance, and usually (but not always) set a
fault code when they're starting to go bad, but the front oxygen sensor
can cause this.

Also I didn't notice any mention of the air filter. And there's nothing
to adjust.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

My owner's manual (for 2000 S70 indicates that timing belt should be changed
at 105K miles. Don't know if that'd have anything to do with mileage or
not. I'm coming up on that shortly, but my gas mileage hasn't changed.

 

Thanks Mike and mdrawson! I'm sure air filter and timing belt are not
the concern. Air filter has been changed at 30k interval and the
current one has been used for less than 10k miles. Timing belt was
changed at 90k miles.

I don't think the brakes are malfunctioning to cause reduction of MPG.
But I'll try to double check.

Actually O2 sensor is the one I'm suspecting. But there's no sign (like
Check Engine light) for its going bad. Wonder if it's worthwhile just
replacing it for a change.

I am also wondering about other things like a new set of spark plug
wires (stock ones still used) or something else.

There got to be a reason. Not only the MPG has dropped significantly
(more than 20%), I can also clearly feel that the horse power of my S70
is much worse than before.

I'll appreciate any thoughts or input.

Thanks.
WHC

 

I have a '99 S70.

It gets about 29-31 on hiway, and about 24 in town.

j.

 

It's a bit hilly in my area. For instance there's about 900ft altitude
change between work and home, though it's only 8 miles. So slightly
lower gas mileage is expected. But my concern stems from difference
between now and one year ago with the same style of driving.

Yesterday "Check Engine" light came up. Maybe something is indeed
wrong. I'll try to find out what code it is by using my ODBII reader.

WHC