I just finished doing a full PI swap on my 96 GT and after putting the car back together, I am getting this unidentifiable noise coming from the motor. It's a very metallic noise but it is not a constant steady rhythmic noise. Its random, with different frequencies, it will slow and speed up at random but is always there. Weirdest of all the noise fades on goes away completely when the engine is revved up. The motor sounds extremely strong and is not misfiring. I have gone back and removed the valve covers and intake manifold and put a bore scope down the spark plug holes and into the intake runners to see if anything was in the cylinders but I could not find anything. I removed the x-pipe and ran the car with open headers and its still there. I am at a loss for what to do. I do not really want to take the heads back off but I am running out of ideas. If you guys have had similar problems or can give me some ideas I'm open for anything. Thanks