bad gas mileage

i have a 96 toyota corolla which has been in da family since it came off da lot. the problem is with the gas mileage. ITS HORRIBLE. for some reason gas usually wont even last an entire weeks time. the gas needle can be watched going down often while just going down the road. i tried changing the fuel filter (pain in the ass to get to and change but it was worth it-saved $100 on labor charges) but no success. i have a short ram and an a sports muffler which are both said to make some difference but none has come my way. spark pluggs and wires were changed about 6 months ago, NGKs were used. i also tried some fuel injector cleaning agents from local store but there was no success there. i think it could be an even bigger and more expensive problem than the fuel filter like the fuel pump. from what i've gathered so far, their much more expensive and much harder to put in than the fuel filter. :eek: some say it may jus be the gas moving around in the tank but thats not it because it move every single time i stop and it doesnt. i thought it could be the speeding but i slowed and did the speed limit after a fillup and gas went seemingly faster than when i was speeding every where i went. im wondering if it is a problem in all older corollas but some say they get great gas mileage. im unsure of what to think or do.

Is anyone familiar with or having similar problems with their corolla?

Yeah, I recently got a 99 4 door auto, and it too seems to be hard on gas. I have no idea why though. Everything seems to be in order but I still have issues with gas mileage. I know that I noticed an improvement when I checked and corrected my tire pressure...maybe that may affect yours more than it did mine. Its pretty easy to overlook. Plus, cheack your air filter, make sure that isn't clogged.

whats your gas mileage?

I get max 34mpg highway but avg of 30mpg.

If you arent getting those I would check intake for carboning.