I topped off my car today and I only got 18mpg.
81 miles, 4.4gallons = roughly 18mpg.

I will let you know what is done to my car.
Cone filter, 2.25" cat-back exhaust, cobb pulley, neon coil upgrade, oil catch can. This is a 2.2 out of a 95 legacy. I am running stock computer. Manual transmission.

Does anyone else get this low mileage?!

I take the freeway to and from work, I do very little street driving. I do have my spurts of lead foot, but its not all the time.

I think my car is running way rich, when I take off, I see smoke from behind my car upon acceleration. My friend was following me one time and I accelerated and he said he smelt unburnt fuel. I know I don't have a fuel leak.

Any suggestions? *Other than drive like a granny.

Sounds like a dead o2 sensor. Is your check engine light working?

Yeah Check engine works. It comes on when I turn the key, then goes off from there. I can try swapping out O2 Sensors.
I think I might reset my computer tomorrow.

I have a rally meet Sunday, and I don't want to go through gas faster than I go through Dr Pepper. lol

Well reseting my computer seemed to make it worse. I can watch my gas gauge drop as I drive. lol
I am going to check my O2 sensors and maybe run some Seafoam through the car, and check my spark plugs, tomorrow after work.

Are you running stock size tires? Does your speedo read accurately?

Also, don't freak out based off of 1 tank. You should check your average mileage over 3-4 tanks and see how it does.

The fact that there was smoke upon acceleration points to a bad O2 sensor. Replace it and your mileage will be happier.

Stock tire size. Speedo is accurate.
I will try swapping out O2 Sensors after payday. :D

Another thing I was thinking was how my outback had a leaky (rusty) fuel filler neck. Needless to say my fuel economy suffered.

Yeah I checked that first thing. :/ And I took off the plastic piece, and it looked fine, and I didn't smell any fuel either.

That made me lol for some reason.

Alright so I think I found out the culprit here!

I had a nasty exhaust leak. One of the welds on my header got a nasty crack and over time un-welded half the pipe. So, I tossed the stock header back on. Also while doing that, I found that the ground wire on the O2 sensor was snapped and just touching. So I replaced the O2 Sensor. Which was black as could be and somewhat oily. Which brings me to my next fix.

I got rid of the smoke that was in my exhaust by switching the Oil catch can over to the oil breather for the heads instead of the crank vent, then ran from the catch can into the intake. Bam! no more smoke in exhaust, seemed to help with the running rich issue as well. So I killed 2 birds with 1 stone there!

While doing all this I noticed I had a nice oil leak from the camshaft seal on the rear of the passenger head. So I am hoping to get that fixed as well, and since I get to change my oil, I figured doing an oil pan gasket wouldn't hurt.