Your filter is going to be under the car, probably near the gas tank. It is not hard to change, just two fittings on the lines to loosen, and the clamp that holds it in place. Sometimes the fittings can be quite stubborn, if the filter is old. If you dont have line wrenches or two good vice grips, you might end up mauling them too badly to be reused, so don't get too cowboy with them. Also be aware that the lines are under pressure, and fuel will spray when you first crack 'em , so watch your eyes! Make sure the new one is oriented the same way (they are marked inlet and outlet) and if there is an o-ring on the lines, be sure to put it on before reassembly, otherwise it will leak no matter how tight you get the fittings (fast, too!) I had that motor in a 1991 Olds Calais, and after I sold it, there was a similar stalling problem. The guy would never leave it with me to check it out, and on a trip at high speed on the highway, he blew a hole through a piston. His EGR valve was getting hung open, causing a constant contamination of the combustion with cooler gases, which finally stressed 1 piston beyond it's limits. If the car will run normally as long as you are giving it throttle, this could be the problem. I have had good luck giving EGR's a little whack with a hammer, if the jar causes them to seat, the problem goes away temporarily. Then you know what to replace. Keep us posted, and I'll see what else I can think of. P.S. the torque coverter lockup problem typically causes stalling after driving for some time, then coming to a stop. The motor will die, just as if you were driving a stick, and forgot to push the clutch in. (essentially, that's what's happening) It will restart easily, but be slammed to a halt every time an attempt to put it in gear is made. Once the car sits for some time, the TCC solenoid bleeds off pressure, releasing the lock-up, and everything works normally again, until the next episode. I am almost sure that is not your problem.