i need to know how to remove the gas tank from my 1990 Ford Thunderbird

Why? The fuel filter isn't in the tank. Sorry, I shouldn't question - must be a shot pump right? Well - first - is it a rear or center (under passenger seats) mounted tank? First you should have the ass-end up on ramps. Then you need to depressurize the fuel system and remove the battery cable(s). Then you must empty the fuel tank of gas. Then you uncouple the fuel lines with your uncoupling tool (spring expander),etc. (Make sure your garage door is open for the gas smell). Then put a garage jack with a fairly wide board on it under the center of the tank (but not under the tank straps). Then -if now possible- unplug the electrical connector (else wait 'till the tank is dropped a little). Next remove the tank strap bolts and pull them out under the tank. Slowly drop tank and remove electrical connector if not already done.