I have installed ouple of fuel pumps in my 2002 Camaro SS conv as it sits a lot sine I retired. Basically the fuel pump won't turn. Okay I have the sheet metal cut from inside the trunk so its easy. I may have been doing something wrong here even though I am a professioal mechanic of 40 years. My what I mean is that I may hav ebeen double gasketing the large o ring gasket which seals the pump to gas tank ! First two was not too hard but the flange was not easy to latch onto but I managed, I examined the fuel tank inside to see if their is any trash in there - a little so I cleaned it out. Cleared the neck of the fuel pump opeing and I see a hard rubber gasket embedded in their.....I have been installing the large o-ring gasket on top of that!
NOW is this the way it suppose to be or am I to dig the original embedded tank gasket and use the provided new one ? Putting the new pump withut the provided gsket is too loose even with flange cranked down to the stops. Any info in regards to this is appreiciated.... I have installed hundreds of pumps intank and never encountered a gasket that looks as if its part of the gas tank!

 

my 93 didn't have anything but looking at this video at 3:55 you can see what looks like a rubber lining on the tank under the o ring.