Oldsmobile/Buick Repair: 92 achievafuel gauge bobbing, gas tank, plastic pan

Question
I Recently inherited my dads 92 acheiva 3.3L v6 from my dad thrpugh hand me downs. The car was great when he had it and then it began crapping out on me at 127k. Basically after i start the car the gauge usually reads something around full,when speeding up or slowing down it will flutuate massively. Sometimes its right most of the time it's way above. It never fails to read wrrong below an eigth of a tank. low fuel light will turn on even if the gauge reads full and is really empty. Throw me a bone here man I'm in over my head in electronics.
thanks ahead of time

Answer
Either the fuel sender n the fuel tank is faulty or in the gas tank there is what is called a BAFFLE which is no more than a plastic pan 12" square that is attached to the inside of the gas tank and occassionally this baffle comes loose and causes this problem.

Once you get the sending unit out of the gas tank you can stick your hand down in the tank and feel for the baffle to see if it came loose. If it did, you will have to replace the gas tank.