Gas Mileage

I have a 4 cyc 95 and it has always gotten decent/good gas mileage but the past 2 weeks or so its really gone down. I put gas in last wednesday, put it to on the high side of 1/2 a tank. The only driving i have done since then was home from the gas station (maybe a mile and a half) then to school and back thursday, not even a mile one way, and i just kick it into neutral 1/2 the way to school cause its all down hill. then the same thing friday, except the school run twice. saturday i drove maybe 2 miles, sunday i didnt do anything. It is already down to almost a quarter tank. what are somethings that would make the gas mileage go down that much or whats going on??? thanks...

You think someone may have stolen your gas?

No. my tank door has to be unlatched from the inside of they car, plus If they were going to steal gas they woulda taken more. i have been watching it go down.. and it has been going way faster than it should

Has it been cold were you live?

2-3 weeks ago we had cold/rain/freezing temps.it has been in the 50s or so lately though. somethin else i probably should mention was about a month ago my brake light wouldnt go off and when i put brake fluid in it did and hasnt come on... maybe something with the brakes sticking? it really doesnt feel like the brakes are sticking or anything though and its not making any odd sounds...

i dont know if there is any truth to this but i was told by a mechanic that the cold weather has something to do wit it and also you might check your fuel filter