fuel guage started out working only until it got to 1/2 tank then would drop to empty, now even when tank is full it drops to empty moments after starting the car, wondering if i am correct assuming the fuel level sensor is junk. Any advice would be appreciated!

Replace sender.

would that be located on the fuel tank
thanks for your input

Yes, and should able to just purchase the sender, not the whole unit.

kinda wondering since some cars have access to the fuel pump underneath the backseat would it be advisable to cut a hole to access the fuel pump with a tin snips, just an idea crazy enough to work

I have never done it, I just drop the tank. Not that bad, with pump working you can at least drain it.