Bizarre miss firing problem

My 1990 Toyota 4x4 pickup's 3VZ-E 3.0 L (2958 cc) engine suddenly began to miss fire. By the end of the trip it was running on 4 cylinders.

I isolated the miss fire to cylinders 3 and 4, by removing each spark plug lead.
All cylinders have strong spark. I changed the spark plugs, and used a heavy dose of injector clean with no improvement.

A compression test has 150lb in each cylinder.
Next I pulled off the top end (intake). All injectors are working and there is no resistance in the injector solenoid wires. (no broken wires)

Oh yes, the rotor, cap and leads are all new within six months.
I do not have a official Toyota service manual, have no idea of the wiring schematics and know little about the computer that reads and controls sensors, ignition or injectors.

Has anyone every had a similar problem? :disappoin