Fill up problems

[a4_matt]

So, for the past couple fill ups my tank has been giving me problems... I noticed it whenever i had "filled" my tank up, but got in the car and it was only 3/4 full. and realized how much i put in and it added up. Then today, i went to fill it up, it just went below 1/4 and only 9 gallons would go in and it says i only have 1/2 a tank... i let it sit, for a second and tried to put more in, but no more would go in.... any suggestions to what it could be? Also, my gas mileage has been really shitty... like 18.5 consistently, i saw other posts saying to check fuel filter, and 02 sensors, and such... what are things i could do myself (i have very little car DIY knowledge, and my roommate has some -- on his honda, but its still a car).
TIA,
--Matt

[AudiA4Turbo22]

oh u have the erratic gas gauge problem:

scroll down it'll say erratic fuel gauge fix!

http://www.audiworld.com/tech/elec.html

[a4_matt]

cool, thank. i'll have to try this tomorrow.

[a4_matt]

bump....lol

So, I never tried the DIY b/c i have an extended warranty through the place that i bought the car from. Think it's covered by the warranty. I mean, my turbo and all the other engine problems i have had have been covered... and when i tried callin the service ppl, it's all automated... so what do you guys think?