Interesting. Your problem sounds a lot like what I'm experiencing when ever I start my car in the morning or when my engine is cold. It's really loud and annoying. I know it's not the alternator or the belt or the water pump. Those checked out fine. I checked the belt tensioner and I sprayed it with WD-40, but that didn't seem to help it at all either. Originally I thought it was my starter going bad, because the sound was like the bendex was not disengaging, so I bought a new starter. Nope, that wasn't the problem.
So, I was thinking it could be my coil pack. In fact, I'm waiting for it to be shipped in so I can replace it. I don't even know if that's the problem. I've been getting different responses from different people. Even some of the mechanics that I have taken it to, don't know what it is either.
I have a '99 w/a Duratec and I don't have a distributor or a cap.