My wife and I both have 95 impreza outbacks with auto and 2.2l Mileage is similar. Here is the weird part:

 

Mine, slightly worse gas mileage, but feels much faster then hers. I do not notice any stuttering, hers just seems flatter across the rev range.

 

Is this something a tuneup can fix? maybe a fuel filter issue, or is there any other reason for this?

I'd look for a vacuum leak first.

When was the last time it had new plugs and wires put on? PCV valve? Ever use any fuel system or intake cleaners? MAF cleaner?

Plugs about 10k miles ago, wires who knows, I havent changed them since I bought it. No to all the rest.

Could it be from dirty EGR valve too?

are the tires the same size?

yes and steel wheels on both

My wife and I both have 95 impreza outbacks with auto and 2.2l Mileage is similar. Here is the weird part:

 

Mine, slightly worse gas mileage, but feels much faster then hers. I do not notice any stuttering, hers just seems flatter across the rev range.

 

Is this something a tuneup can fix? maybe a fuel filter issue, or is there any other reason for this?

How about storage in the car. I used to carry about 150 pounds of tools and parts in my car; it does really affect the fuel consumption.

nah I think weight wise we carry about the same. It is strange it almost feels like she has a smaller engine since it gets better mileage but less power. They are both definitely ej22s though. Will probably just start with a tuneup though. We have owned it for 40k miles and all I have done is oil changes, brakes and new spark plugs.

Are the gear ratios the same? Lower gear would give faster acceleration and lower MPG. Easy way to check that is to take note of the engine rpm at a given speed when the car should be in its highest gear, say for example 60 mph. If the gear ratio is the same, the rpm should be the same in both cars at 60.

knock sensors, dirty maf, coolant temp sensor, the age of all those greatly affect mileage.

If one has had the heads replaced and upgraded to roller rocker cams that would do it.

I thought the 95 ej22 all had roller rockers?

Some of the early 95 ones might have still had flat tappet rockers.

My wife and I both have 95 impreza outbacks with auto and 2.2l Mileage is similar. Here is the weird part:

 

Mine, slightly worse gas mileage, but feels much faster then hers. I do not notice any stuttering, hers just seems flatter across the rev range.

 

Is this something a tuneup can fix? maybe a fuel filter issue, or is there any other reason for this?

 

I`ve seen this on other cars w/identical drivetrains.

Compression differences seem the most obvious answer.

 

I think a stack-up of production tolerances that affect ignition/valve timing,fuel delivery and compression is the real culprit.

 

Might be worth comparing fuel pressure between the 2,but,I doubt it.

cat on the wifes car could be more pluged as well

or you just have a wednesday car

Well the tuneup is going to have to wait. Her hours got cut at work so no money for tuneup parts now, just oil changes. Back to the "only fix things when they break" mode. Will let you guys know if I ever figure out what the difference is between them.