Ok, '91 22re 4WD with 163K miles

I get a rattling noise that has progressively gotten louder over the last few months. Initially it could only be heard while at full throttle, but now you can hear it at any speed or rpm. This happened to me about 4 years ago and turned out to be the water pump going out as it was leaking and the shaft was broken causing the fan to wobble, so I replaced it with an non OEM pump.

Thinking that the pump was the issue again I began to disassemble everything to remove the pump. Here is the catch: the pump spins smoothly and freely and there is no play or wobble in the pump shaft. Maybe not the water pump? Or could it be:
1. Timing chain slapping
2. Another pulley going out
3. Rod bearings

I am pretty much at a loss for what it could be, but I don't want to risk putting everything back together and continue driving the truck as it is my daily driver (only vehicle) that I put 60 miles on a day.

One more issue, I have been unable to remove the power steering pulley, even with my two arm pulley remover. It just won't budge and I do not want to risk bending the pulley. Any ideas??

You may have better luck with a power steering pulley remover. Not sure why you need to remove that pulley.

In order to get access to remove the water pump I need to remove the bracket holding the upper belt tensioner pulley, that bracket has a bolt which is covered up by the p/s steering pulley. Anyway, I was able to remove it but I still don't know what is the cause of the rattling. I think I may just have to put everything back together and drive it until something rears it's head as the problems. At this point I can only guess.

For the PS bolt, it can be removed without removing the pulley. Just use a 14mm wrench. I use a ratcheting box end (autozone has them). Comes out fairly quickly.

Are you sure that you are not hearing an exhaust leak? Feel around the exhaust manifold near the firewall. Usually where the gasket seems to go first.

Or,
drop the oil pan. If there is old timing chain guide pieces blocking the oil pickup tube........ Rod bearings.

Yep, drop the pan. Probably have chunks of what used to be your timing guide. Just had mine do the same, not bad at first, but rapidly got very noisy at all rpms.