so while i was out driving my car last time the fuel guage would go all the way up as high as it go go above full and stay there until i would get off the gas. then it would go back down. if i turned it would also go back down. i don;t know what is going on but it only goes all the way up when i am on the gas pedal. is it shorting somewhere or grounding out or the sending unit going bad. anyone hav an idea

 

thats how my 91 rs acted and it was the sending unit. that over 500 from gm and like 250 from napa. but that may no teven be the sending unit it could be a gauge go to the yard and get one outta a car and try the new gauge see if that fixes it.

 

It is the sending unit and this will happen quite normally because the gas is sloshing around in the tank since it is a non-baffled unit.