when you replace the pcv valve, replace the grommett. if, and it likely is, the grommett is dry and cracked, it can cause sputtering and rough idle until warm up and if it is real bad, the roughness will continue.
Talked to the owner over the phone and he said the truck has an unidentified oil leak and uses apx 2/3 quart between changes. Does the fzj80 have the rear main leak like the earlier ones do?