need help here

i have a 1997 Mazda MPV 4wd 3.0 I just did a computer check on my car because the check engine light came on and it says P1445 which is a fuel tank level sensor circuit. now what is this????

now my fuel gauge has been sticking since i bought it a year ago. when i go to fill my car up the level will go all the way to full and when it gets to about 140 miles it will drop to empty and i have been going on the mileage when to fill up. how can i find this and where do i go to get a part for it. also will i fail an inspection as well with this light on?