And then she went bang

I'm still trying to determine an issue on my 2RZ. Now that it is colder out, a problem with hesitation has become more predominant. When the engine is cold, it starts just fine but as soon as I pull on the road, it has very little throttle response. I can push the pedal down 50% and she will move slightly faster than an idle speed. Other mornings, it drives without a single problem. The issue always goes away once the engine starts to warm up (actually, within 15-20 seconds the problem is gone). I figured the TPS might be at fault even though it's passed each time I've tested it when it's cold. I had planned to buy a new one anyways, until yesterday.

I pull out onto a main road and had forgotten about the possible hesitation. Of course, at the time the truck went no where. I pushed the pedal down to the floor and that is when I got two, loud, distinctive back fires up threw the intake manifold.

So this is my conclusion so far;
TPS shouldn't cause a backfire like that
A stretched Timing chain should cause the problem on every cold start.

Possible faulty crank sensor? Possible plugged cat? (although no problems persist shortly after start up) I'm at a loss.

'98 Taco, 195k, 2RZ

 

Plugs are brand new and I just installed a set of Dealer wires last week.

 

Cap and rotor on that one? If so, replace it.

 

Check for vacuum leaks; pcv hoses, EGR, intake manifold, air intake chamber, throttle body, brake booster

 

Two Coils, No cap and Rotor. Both coils Ohm out correctly.

The PCV hasn't been replaced. I'll do that today. Intake/Throttle body just got resealed during my hunt for this problem. I seafoamed the intake and engine and it's much cleaner but didn't change anything.
I also cleaned the Idle speed controller (highly recommended).

I'm going to try and hunt for a possible vacuum leak.