93 Ford Aerostar van

You mean the torque converter, which is related to the transmission. Possible. If you think you can perform this test safely try this. With emergency brake on and your left foot on the brake pedal try giving it a little more gas as you shift into drive. If the engine keeps dying no matter how much gas you give the problem most likely in the transmission. But I suspect the problem is related to the engine in terms of performance. Any trouble codes or check engine lite on? Last time tune up was performed? Clogged fuel filter? Get the picture. Probably a bad sensor(s) is causing your problem.