99 Camry 1MZFE Cyl 1,3,5 misses

[timekeeper15]

I have a 99 Camry V6, California emissions model, that has an intermittant problem. It will run very rich and throw random miss codes on cyl 1,3,5. It will run fine for as long as a week at times and then start acting up with poor mileage, power, and jerky running at all speeds consistant with a missing engine. In an attempt to correct the problem I have installed new plugs, and wires. I replaced one coil pack and moved it to all 3 spots to see if that helped (it did not), I've had it to the Toyota dealer 3 times and they cleaened some carbon off of some sensors and ports on the engine as well as replaced an O2 sensor on the offending bank exhaust. I have had it to 3 independant repair shops, 2 that could not get it to act up and the other I had change the EGR valve to see if that helped. Iv'e Googled and Yahood the internet with very liitle feedback on this problem. It looks like my next option is to change the injectors but I wanted to see if anyone here could give me any other ideas.

Thanks,

Scott