the idle air control valve only affects the engine during idle. after that air enters the engine through the open throttle valve inside of the throttle body. So it is doubtful that this causes the car to stall while driving down the road.

once it stalls, what do you have to do toget it going again?

Check the fuel pressure as you are driving it, especially when it stalls. could be that the fuel pump is starting to fail.

Thank you for your help.

I usually just let it sit for a few minutes. The fuel pump failure would not show on the computer?

not fuel pump failure would not show on the computer. However, it would show as low/no fuel pressure once the engine stalls, that is why i suggested you check the fuel pressure while driving the vehicle. even after it stalls fuel pressure on a good system would remain high and slowly decrease over a period of 15 minutes or more.
if your car starts to stall and you notice the fuel pressure is near zero, this is an indication that either the fuel pump is failing, fuel filter clogged or a severe fuel leak.