After reading about EPR valves, etc. I'm now wondering if I'm going to have problems since mine was not removed? What exactly will happen if EPR remains?

Also wondering now if I should evacuate system again and drop in Freeze-12? Would I have to flush all or part of system? BTW, I filled the system with about 7-8 oz. of Ester oil before I added the R-134. They say that Ester is compatible with either 12 or 134 oils. So what about the oil that was in the 2 cans of 134? Would this cause a problem if I went back to Freeze-12? Or, maybe I should just let it fly as is?

Thanks for any and all help! Sorry for all of the questions. Not really well versed in auto a/c and no one wants to fool with anything this old around here.