engine stalls

It's hard to say considering I have no information or history on your Sub. It's possible that the fuel pump is picking up air and losing fuel pressure causing the engine to stall. It could also be that there's carbon fouling in the throttle body or idle air control (IAC), or that the gasket under the throttle body is defective, either could be affecting the computer's ability to control the engine. If you want to find a GM specialist, here's our directory link for you: https://repairpal.com/chevrolet-repair-in-new-milford-pennsylvania

sounds like torc covertor problem