Remember I said ONE of the purposes of the thermal valve was to kick up the rpm. The second purpose is a "hail mary" attempt to cool down the intake in the event of your coolant overheating. If the coolant overheats the valve will open, by-passing the throttle body, and opening the air path between the intake tube and the throttle chamber. That will introduce some cooling air. You should leave the rubber tube on between the plastic throttle intake tube and the thermal valve. Cap the upper outlet facing the throttle chamber and leave the lower tube connected to the throttle chamber. It will be a rare circumstance if you need it but I assume the engineers who designed the engine didn't put it there by accident.