1996 Oldsmobile 88 gas tank / fuel line

I'm having an issue with my gas tank. I've replaced twice and keep getting a dent in the same location on tank.
every once in a while I get a little pressure coming out of the gas cap area when I open to fuel. I smell fuel around the car now. I've had two mechanics look at the care and both cannot figure out. They say I don't have enough pressure that it is caused from the inside of tank. MY GUT FEELING TELLS ME IT IS SOMETHING INTERNAL, but I'm no mechanic. Both state I must be bottoming out. I have not bottomed out nor am I hitting anything. No signs around frame of gas tank that sit lower show me bottoming out or hitting anything.
I've had lines checked and no sign of leaks. I believe the silenoid has also been replaced along with a new gas cap. Can you please give me your thoughts to move forward and get fixed so that I can get a new gas tank with fuel gauge so I don't have to monitor my miles.
I would really appreciate it.