Something maybe be wrong!

[xchronicx]

Hey guys im new to the Legacy Forum i recently purchsed a 97 Legacy L sedan off a friend.. i recently put intake and exhaust on and i was worried because my gas mileage is extremly low.. i fill up my tank all the time! i filled the tank past full and now on wednesday im a quarter tank!! is there something wrong with this or?? Also do u know if getting my cats hollowed outy will make a performance difference? thanks guys

[petridish38]

good question... my friend has a 96 Legacy and she is having similar issues. she can only get around 200 miles before shes at 1/4 of a tank. I suggested that she try to drive around until her fuel light comes on as her guage could be off or could move really slow after 1/4 tank.

Of course she hasn't done this yet as she is "scared" to let it get that low.

How many gallons does it take when it is "empty" and how many miles do you get before it is "empty"? have you let the fuel light come on yet?

[entirelyturbo]

I wish I made 200 miles on 3/4 of a tank

Follow in my path and look into replacing your O2 sensor. I am probably going to get a 4-wire O2 sensor and use that extra wire to ground to the body instead of the rusty old exhaust, so the sensor will be more accurate...

[THAWA]

seriously, i barely make 200 miles before I'm at the line nowadays. Dunno what is wrong :\

[scottzg]

i look to intake and exhaust mods.

My economy was piss poor when i was driving 10 miles up a severly windy mountain with a cone intake. I got about 170-tank. Now, with what is basically a stock airbox doing the same use, i get about 240, around town i get about 350 (356 to be exact ). I'll admit im a bit of a throttle jockey though.

--real information starts here--
Floppy exhaust and intake make the car idle less fuel efficiently than ideal, they also affect your low end, the car loses its smooth flow of air. Try blipping the throttle to see this effect. Beyond the point where the vacuum is filled by sucking from the engine rather than the spreading of the atmosphere (i hope that makes sense) is the only time when large exhaust and intake is benefitial to power and economy.

i would look at would be things that mess up the even supply and correct ratio of air and fuel. This would include not enough fuel because of an old pump, poor dispersal by craptastic injectors, any air/fuel/exhaust monitoring sensors, cat, etc.

Your last possibility is to check if you have some horrid parastitic loss. Too thick fluids in a tranny, engine, or diff, binding brakes (doubt it).

This is probably way further than the problem is, my guess is the mods or a direct result of the mods, like a dead maf or something. Good luck.