This is where I found a hard-to-find vacuum leak on my Ford 4.6 liter 2 valve V8 engine. These engines were put in cars and trucks, the Crown Vic, The F-150, and the Mustang. This is the vapor tube assembly between the EVAP purge valve (AKA, the vapor management valve) and the throttle body. The old tube (hose) was completely rotten and became very porous. I believe air (vacuum) was leaking directly into the engine through the porous walls of the old hose. The new hose is actually a plastic tube and comes with new quick disconnect ends already installed on each end. This was absolutely causing a vacuum leak (Pirate Air) on my vehicle, which I proved to myself with a pinch off pliers. If it happened on my car, it can happen on any other Ford with the similar setup. The new “EVAP Tube Assembly” came directly from Ford and it was fairly cheap. Nice, easy, quick fix. Hope this video helps someone who will eventually find themselves in my shoes trying to find the source of high positive long term fuel trims.