everyonce in a while my fuel gauge goes all the way down to empty then makes it's way up. does anyone know what causes this? it seems to happen mainly when i fill up the tank completely.

 

That could be a couple of things. Your fuel guage may be going bad (have U had this problem in the past??), of the 'fuel-thingie' that senses how much fuel you have (gosh, I'm having a bona-fide BRAIN FART today..)may be malfunctioning. I don't know if that thing is in-tank or not, so I can't give U specifics on it. There even could be a short in the wires somewhere. You might be better off taking it to a decent mechanic to have them check your electrical system. Good Luck

 

i just got this car a week ago from my uncle and i've filled it up twice and it did this both times.

 

It sounds like the sending unit (if I only had a brain, I'd have remembered the name of that thing in the first place) may be bad. Looks like a trip to the mechanic for ya, unfortunately.