"a dead hole" usually means that one cylinder is not making power. Could be several reasons for this.
Ignition, fuel, compression.

You say it runs well when cold. If compression was bad I wouldn't expect this, but, since you haven't done a compression test yet it might not be a bad idea on an engine with high miles. You can buy a compression tester for less than a dealer will charge for one hour of labor if you want to do it yourself.

You also say it stumbles at low rpm, then "just revs up". I'm not sure exactly what you mean by this. When it "revs up" does it have normal power?

BTW, did the truck ever run right while you've owned it? If so, how did the problem begin? Was it
gradual or sudden?

Couple of things I would consider. When you changed the cap and rotor did you use genuine Toyota parts? If not you might want to, I've had bad luck with non-oem ignition parts.

Since you have to remove the sparkplugs to do a compression test anyway, I suggest you replace them with normal ngk (or ND) v-groove plugs. I've heard that platinums don't work too well in a 22re, don't know why not, and can't confirm with first hand experience, but a new set of plugs is pretty cheap.

Now how about those plug wires. Do they test OK? Any worn spots in the insulation? Maybe somebody pulled a wire out of the boot by pulling on the wire to remove it instead of pulling on the boot.
If they are suspect, you might want to replace those as well.

It could also be an injector is not firing properly...

BTW, keep everything you replace and carry as spare emergency parts.

Like I said, a compression test is a good idea.
One more thing to try before you spend any more money. Try driving it with the TPS sensor disconnected. Just pull the electical connector out. This will prevent the computer from going into closed loop mode. If it runs fine that way check all the sensors - especially coolant temperature, and AFM.

I assume you own a service manual. Does the trouble shooting section have anything useful?