Chevrolet Avalanche 2002 P0300 Code: Possible Leaking Injector Diagnosis and Fuel Pressure Issues

My 2002 Chevrolet Avalanche has reached 90,000 miles. The engine starts smoothly when cold and has sat for at least 6 hours. However, when warm and after a 5-minute rest, it takes an extended crank time to start—typically setting fault code P0300—and runs roughly for about one minute before returning to normal operation. This roughness only reappears during prolonged stops, such as at traffic lights. Fuel economy has dropped by approximately 2 mpg on highways. I have already replaced the spark plugs and plug wires, as well as the air filter. Notably, when the throttle is opened during warm starts, crank time significantly decreases. Fuel rail pressure readings show 47 psi at idle, with minor fluctuations (within 3 psi) when throttle is advanced or released—no significant changes otherwise. After engine shutdown, pressure drops from 47 psi to 10 psi within five minutes, which is slower than expected. When starting the engine, fuel pressure jumps to 47 psi before the crankshaft completes a quarter revolution. During warm starts, I often detect raw fuel odor in the exhaust immediately after ignition. Additionally, removing the air filter 15 minutes post-shutdown reveals a noticeable fuel smell inside the air filter box. Could this indicate one or more leaking injectors? During plug replacement, only one plug appeared wet; currently, all plugs appear dry and uniform. How can I accurately identify which injector is leaking? Should I consider removing both fuel rails and performing a pressure test to diagnose the issue?