Hello, I have a friend with a '95 Camry that sputters (only when idle) and occasionally stalls when switching between reverse and drive. It still occurred after a trip to the mechanic, and I found a line disconnected that went to the engine. I have no idea what this part is but after it was taped up the sputtering seemed to lessen/stop entirely. Any advice on what the part is/other potential causes to this problem would be appreciated.

Overall view.
The taped part.

 

Temperature Vacuum Valve (TVV).

Temperature controlled on/off valve that turns vacuum to a hose on/off.

The small hoses run between the charcoal emissions canister and throttle body vacuum port.

Its threaded into the cars coolant system. When the coolant reaches a certain temp, the valve opens.

When the valve is open. Fumes stored in the canister from the gas in the fuel tank, are sent to the throttle body to be burned.

Since one end of the hose runs to the throttle body. If that hose is not blocked or connected to the valve. Excess air will enter the engine and result in the problems you have.

Replace the part (note will need to drain out some coolant). If just a plastic hose nib broke off the valve, glue it back on.