maybe its my gas tank?

[entermymatrix03]

hey guys, new here and i don't drive a mustang. i drive a 2003 toyota matrix. no flames please. i'm jerri's (stang_grl617) BF and i have a problem with my car that maybe some of you could answer, or she thought so. lets get to it shall we...

ok, this is gonna be hard to explain. you know how when your filling up and when your tank gets full the gas pump kicks off until you pull the nozzle out some? well mine has been doing that after i put like 1.00-1.50 in my car. it keeps doing that until the car is full. i've tried different hose depths and i've tried 3 different gas stations because i thought it was the pumps at first. i've been to the same station twice and both pumps did it and then this morning at a completley different station and it did it there. i know my luck isn't that bad! i used to get 360 miles to the tanks and the previous fill up before this one got me 300 miles and before this fill up i got 345. i do run the AC but that isn't gonna rob 60 miles out of a tank!!! 20 or so i can see, but 60?!?! anyways, if you guys know what in my tank is making the gas pump kick off every dollar and a half please let me know what i can do. i hope i have explained this good enough. thanks.