I'm not really sure if I can say it is an engine noise or a possible pulley noise. The engine is very quiet except for one moment in its run. The noise seems to come from the front area of the block (Belt side). During moderate acceleration all is quiet until just before the trans shifts to second. It only lasts about 2 seconds. I at first thought it was knock but with the windows open yesterday I don't think so. It actually sounds like how a bad harmonic balancer sounds at idle (marble like). Kind of sounds like a bearing noise of sort, almost like something (crankshaft) is spinning out of control momenetarily. I know it might be tough from my discription, but any ideas? The car is quiet except for this moment and the trans and engine run smoothly.

I know the description is vague but someone must have some thoughts. :?

As a start - remove the serpentine belt, and give each pulley a spin. Include the water pump, and alternator. Anything seem to bind or feel strange?

Still haven't checked the pulleys yet but I do not believe this is where the noise is coming from. The noise is there a start up and anytime I accelerate heavily and in between trans shifts. At idle with the car in park there is no noise at all even when I increase rpms to 2k. Could this be flywheel and/or timing chain noise. It sounds like a rattling noise. and it'* coming from the belt side of the engine only. Engine is real quiet except for the stated moments.

Check your PCV valve for proper o-rings and seating. The way you describe it makes me pretty sure on the diagnosis.

I just replaced it a few months ago and I transfered the o-rings from the old to the new. I'll double check that.

I checked PCV value and found it in place correctly with both O rings. I did find that value was a little "sticky" and cleaned it out. It rattles good now. I placed it back in. Engine noise is still there but it is a lot less noticeable than before. So either the PCV was sticking or the old O2 sensor(replaced today) or a clogged air filter(replaced today) caused this. I'll keep my fingers crossed!

Does it sound like ping?
Try a higher octane for the next tank and see what you get.

sounds like a supercharger coupler, wait, you don't have a supercharger. That'* your problem right there The supercharger is missing.

No it isn't ping, I know that sound. I have tried premium gas and same result. It is a momentary rattle that gets noisier the more you "step on it" I am getting KS when this happens but no KR which is good. I now believe it is belt/pulley related. The only way I can describe it is that it sounds like a bearing spinning/banging out of control, like that of a bad HB at idle.. At idle there is no noise even with increasing RPMs. :?: