advice, what to do with my 5sfe Options

[95gtschick]

not looking for more hp or anything, but here are my problems:

-start up in the morning lots of white smoke comes out of the exhaust, but never any other time.

-awful gas mileage - lucky to get 280miles to a tank

-replaced spark plugs... didn't make a difference with gas mileage, but stopped my backfiring kinda.

-noticed that a wire was spliced into one of my ignition wires, thus leaving it with a lot less resistance.

-high miles, odometer says 116k, carfax report said that january 2003 my car had 130k miles (odometer has been rolled back).

-burn a little bit of oil

I don't have an exhaust leak, i already got that fixed, i don't know what else to do. Gas mileage right now is my main concern, cause it costs me $50+ to fill up, and it barely lasts a week and a half. What would you guys do? I just want some advice. Thanks

[95CelicaST]

I don't know about GT gas mileage, but I am at 300 miles at half a tank.

Does the white smoke stop once the car warms up?

I would replace the O2 sensor and check your tire pressure, I was getting bad mileage and my tire pressure was off a bunch, so I filled them all up to where they need to be and now I get great mileage.