94 Skylark stalls at stops

I've got a 94 Skylark with a 3.1L engine and a 4t60e transmission. I am stalling at stops and at right turns. This problem is intermittant, and does NOT happen all the time.

I will come to a stop, and the idle seems to either go up (= no stall) or down (= possible stall). If the idle drifts below 500 rpm, the car often stalls. The car can also stall in neutral.

My internet search has revealed 3 possibilities: 1) TCC solenoid; 2) idle air control valve; 3) dirty throttle body. I just don't have the time or the equipment to disconnect the TCC solenoid. Nor can I pull the engine codes. I am selling the car (in the appropriate location) and simply don't want to mess with it.

Question: apart from doing those two things, is there any way to tell what is causing the stall from the symptom list?

It sounds like a vacuum leak. Look where the PC valve is and check the hoses connected to it. Also look in the front of the engine compartment near where the battery is and check those hoses too. I had a similar problem with the engine conking-out and that took care of it.