2002 Honda Odyssey Missfire when cold

This vehicle has a sharp miss-fire starting about a 30 seconds after start-up and ending after about 5 minutes. The miss-fire is random ans seems to be 1 cinder at times and many at times, back and forth. It sets no hard or pending codes, the gas reading from the tail pipe during the period of missing is CO2: 15.3, CO:0.01, HC: 14. Vacuum is 22' and very steady, 0: HC or CO in cooling system. We have replaced all coils, plugs, 2 injectors, cam sensors, crank sensor, O2 sensor, cleaned EGR passages, fuel injection cleaning (pressurized can type), Induction services, adjusted valves, wiggle tested all wires, coil and injector connectors, performed propane enrichment with no change.

Any ideas?

Thanks