and before Bandit screams "fuel pressure" , I'm just trying to eliminate the simple things, and this is why I ask:
I have:
Cracked Manis (badly)
AND
Bad alternator bearings
Which I know contribute to KR. So, can it?

well if the exhaust is Loud enought for the Nock sensor to pick it up at idle im sure t can make it not run right.
also If there is Clean air getting in at idle it can mess up the O2 readings and make the PCM adjust the Air Fuel mis Wrong

No.

Your engine can't possibly be bad enough to have KR at idle. Nobody here does.

ok i was wrong about the it at idle.

But what about my second thought?
i know iv herd others talk about that. :?

I think it'* his cat. I rode in the car on the freeway and on hard accelerations. I could distinctly smell rotten eggs driving on the freeway and after a couple hard runs, also when he pulled away when he left to go home, I got a strong whiff of it. Also his EMs are VERY cracked, as when we did the seafoam, we had smoke barreling out from under the hood when we started it.

Not to get off topic, but has anyone with cracked manis had bad idling problems?

It would seem to be obvious. Exhaust leaks before your O2 will skew your O2s and ruin your LTFT and STFT, Thereby causing a rough idle.

I disagree. There isn't enough gasses flowing at idle for it to have an effect. My car purred like a kitten at idle with horribly cracked manifolds.

Poor idle is either ignition related or a vacuum leak typically. Or a dirty TB.

TB has been cleaned, Ignition has been checked, Vacuum lines have NOT been checked, and it seems like that could be the issue, since I'm not running rich or lean (I don't think) and I've taken them off so many times. I'll get a pressure tester and I'll see what I find

Make sure you have no leaks in the EGR stovepipe from the base of the EGR adapter into the SC also.