I have a 1997 Mercury Mountaineer with 5.0 V8 engine. I noticed lately it's been hard to start and now it's skipping really bad until it warms up. I started listening to the engine yesterday and noticed a hissing sound such as a vaccuum leak. In the first picture, there is a metal fitting where it looks like a hose belongs but I do not a loose hose anywhere nor do I see where the other end of the hose would connect to. When I put my finger over the hole it'has a vaccuum on it and it will shut the engine down if my finger is kept over the hole This area is just under the right side of the intake manifold area (2nd pic). If you have an engine the same size and approximate year, please advise me what's causing this. Thanks in advance.