I just replaced the upper intake manifold on my 2004 mustang gt. I drained the radiator before I started to take it apart. All hole were covered after it was taken out. The new intake manifold came In the next day. I put it on and hooked everything up and now has a loud metal noise when it starts up. It has never done it before. The car starts no problem better than it did before. I it off instantly once I heard the noise. I took off the new intake manifold and checked to make sure nothing gotten down into the engine. I replaced all the plugs and coils and it is still making the noise. Any ideas? The car ran perfectly up until the new upper intake manifold was put on