Can anyone tell me what I may be dealing with here?
 

I haven't been able to crawl under it yet, but it sounds like it may be coming from the bottom or rear of the engine. Possibly in the area of the flywheel. Makes a light noise while driving. Can only notice it when driving past a building. No noise at idle, unless it's in gear with my foot on the break, or the ac is running. The beginning of the video is just to show how much throttle I need to give it to replicate the noise. Any more than that, or anything more than a blip and it goes away. If the ac is running, it'll make a steady continuous noise even when driving, just nowhere near as loud. I've had some torque converter shudder for months now as well.

https://rumble.com/vkvvdx-blazer-engine-noise.html

Two things come to mind:
1. Tensioner pulley is worn out, or
2. The starter gear is out to far, thus causing contact with the fly wheel.

To test the tensioner, have someone put the tranny in gear, foot on brake, with the a/c running. If you don't have a mechanic's stethoscope, use a screw driver to see if that is where the noise is coming from. To check the starter, pull it and see if you have more wear on the end of the gear than the rest of the gear.

Thanks. Turned out the two of the torque converter bolts had backed out. I bought two new ones and noticed that the two holes are not straight. The old bolts came out, and the new ones went in at an angle. Only about half of the head is mated to the flex plate. Don't know if someone has worked on it in the past, and managed to cross thread them both, or if the converter holes got bent from the bolts being loosened. It's nice and quiet now for the most part though. Only if I'm next to building, can I hear a faint sound of what sounds a bolt head making very slight contact on something. I didn't want to tighten the bolts down anymore though, for fear of snapping one.

I changed out the tensioner pulley before looking at the torque converter bolts. Next thing will be the idler pulley. The 2 month old belt has started to squeal when the ac is on at idle, or taking off from a stop,