Asmodeus

I have denso iridiums for about 3k miles, I did them when I put my headers on. I noticed a slightly rougher idle on start up on a cold morning at first. Then I noticed the engine noise got louder. Then I noticed it seemed just a teeny tad down on power. Then I would hear what sounded like a rattle with a rush of air under the hood by the dash when I would let the car coast down with the clutch in, engine braking, from 3-4k rpm's. The higher the RPM's the louder it rattled. As soon as I would touch the gas again, the noise would go away. It did smell kind of like unburnt fuel under the hood, or real bad exhaust.

SO, I checked #6 and #8, did not take either of them all the way out, just one turn loose, then retightened. I tested #8 with my finger and it felt like I could turn the porcelain loose, then tighten it back up. I pulled #2 all the way out to find it's only the metal tip that can screw on and off, and it doesn't take much to do it. The porcelain part should have stayed still?

Does #8 sound cracked? Are those symtoms of something else like a real bad exhaust leak on the header? It just started a few weeks ago, and I did the headers in July. I'll probably just take #8 plug out tomorrow and see though I loathe getting to it.