Low gas mileage on Subaru Outback 2003

run the fault codes and look for problem cam or crank position sensor
could be a problem engine mount that is being started by a misfire

Get a new clutch kit AND flywheel. Don't turn a flywheel more than once, just like with brake rotors. Any car can use an aftermarket clutch replacement (as long as they fit, of course). If you get a lightened flywheel, you'll enjoy better acceleration and mileage (city driving) as well.

If no codes are showing up, but you're fuel mileage has decreased, make note as to where you are getting your fuel. Differently fuel doesn't make a huge difference, but when I worked at a gas station, I had employees from the gas station next to us telling me that our fuel gave them better performance and mileage than theirs did - also, make sure that you're air filter, filter for turbo (if equipped) are new, and you may wanna check your spark plugs, to ensure they are gapped correctly. Another thing to consider is the catalytic converter being plugged, or the muffler even.
Let me know if you have further questions,
carsandcomps

Here is a diagram for the fuse box. Looks like fuse 12 is for the clock and interior lights.
I hop3 this info helps!~subyguru~

loose bolts somewhere in the front end? you have had lots of work done there. wheel weights can fall off or a rim can be difficult to balance?

REPLACE AIR FILTER.CLEAN FUEL INJECTORS,CHECK TIRE PRESSURE.LOW TIRE PRESSURE WILL CAUSE LOT OF FUEL CONSUMPTION.CITY DRIVING WILL BURN LOT MORE GAS,STOPPING VECHICLE THEN GOING WILL CAUSE MORE GAS BURNING, YOU NEED POWER AND FUEL TO GET VECHICLE IN MOTION,BY IT BEING HOT WEATHER, USING AIR CONDITIONING TO KEEP COOL INSIDE WILL CAUSE MORE FUEL CONSUMPTION.

try replacing the gas cap, u may have a leaking pressure relief valve in the cap, this can turn on the check engine light as it is sensing a fuel vapor leak.

if there are no major problems present all it needs is a tune up(spark plugs,fule filter,oil change, air filter, fule injector cleaner). for a upgrade in fuel economy add a short ram intake, parts are fairly easy to install.

I think your (and my) Outback uses gas-filled shocks so the tell-tale signs of leakng fluid will not be visible.
Oddly, Haynes doesn't mention which is standard.

Try the 'bounce test,' it isn't conclusive but it may give you a clue as to whether you have a blown shock or not.

Push down firmly on each fender individually and let it rise suddenly.
Note how each corner responds, if a corner rises a little above static level, then falls back and stops, the shock is probably still functional.
If one or the other seems to bounce a little more than described, the shock is probably toast.
They should always be replaced in pairs.

120 K is a good run for any shocks; they mostly start to lose their function at half that mileage.

low trasmission pressure try changing the oil normally worst when cold check oil level cheers pierre