Cylinders 1-3-5 are 'dead' until roughly 3/4 throttle. I recently replaced the clutch and all 4 02 sensors. Where should I be looking?

You should check the engine compression, may have low cylinders. If the check engine light is on then have the vehicle scanned for trouble codes. I would check the compression first tho.

I guess I should expand upon the question: The vehicle drove into the garage fine and it now has this problem. Otherwise, that answer might have been viable. No check engine light, no codes.

Is there a weak spark at these cylinders? An orange color spark? Any spark?

Without removing the upper intake I can only get to one coil, and that spark is fine. I spent the last several hours looking to see if any of the wiring near the transmission somehow got damaged and I found a 'stub' wire in the signal harness that goes to the passenger front 02 sensor, but I can't find anything it would go to. The two signal wires for the sensor are intact.

I found a wiring diagram so I could check the (insert cuss words of your choice) wiring harness connections for the O2 sensors and found the two front sensors were plugged in wrong side for side. I'd like to have a long talk with a big stick with the guy that decided the right sensor should be plugged in at the very top of the transmission. Problem solved.

Unreal, would never have though this. glad you found this...