OK, you know that the plenum duct is the rubber coupler between the TB and the manifold. It usually develops a rip on the bottom where it cannot be seen. With the engine at idle, spray some Brakleen or such under the plenum while flexing it with your finger to open the rip (if there is one). If there is, the RPM will increase.
The fuel rail remains under pressure once the engine is shut down for quick starts. Look for the schreader valve on the fuel rail (looks exactly like a tire valve). Remove the cap, hold a rag over the service port and bleed off the pressure (just like letting the air out of your neighbors tire). You may get a about an ounce of gas out of it.