Has a 3.8L engine. no codes come up. no check engine light. Help! I bought this car 2 weeks ago. it has only 45,000 original miles on it. it might as well have 145,000 miles. when i test drove it ( 2 diff. occasions) it an fine. no stalling no hesitation had good pick up. then the second time i test drove it it stalled twice as i slowed to a stop. started right back up and that was that. well i bought the car drove it home no issue. later i went to the store and it started sputtering and bucking like it wasn;t getting gas, and was trying to stall. i put the gas peddale to the floor and it finallly caught and had power. about 2-3 min it did it again. when i stopped it stalled. started right back up. now this has been going on since and its worse.i basicaly have to shift it to neutral when i'm coming to a stop and hope when i put it in gear to go it doesnt stall. been taking 2-3 tries b4 it starts, I drove it to a mechanic friends after it sat for 2 days didnt go any faster than 40 mph and it never tried to stalll or have the sputtering jerking hesitation. I've replaced the plugs wires rotor and cap, air filter fuel filter fuel pump(the previous owner said they put new one it well it quit working the other might when my car was being looked at.) checked for vaccum leaks, checked the fuel pressure. nothings worked, it still does same thing. any suggestions what the problem is? Does anyone know where i can get schematics showing the locations of the selonoids.??? Plz help im desperate. i need my car for work. .
also i notice there is a lot of pressure released from the gas cap. I mean a lot. more than i. have ever experienced when getting gas. is this normal. lot of pressure when they replaced fuel filter. gas kept coming out even with the fuse to the pump removed.

 

Sounds like the torque converter lockup. I disconnected mine on my 88 Cutlass, no more trans lockup, but no more annoying stall out. I didn't keep the car long enough to repair it, so I don't know the procedure.

The plug is on the left side of the trans.