Rough idle

I have a 1993 Toyota camry, six cylinder, automatic transmissio. At times the engine idles rough in drive and reverse but not in park. I took it to a garage for a full tune up but it didn't fix the problem. It started doing this about four months ago but went away. So I didn't worry about it. Now it's starting to do it more often and today it started but when I put it in drive and pushed on the gas it didn't want to go. I turned it off and let it set for a while and then it ran fine. I changed the pcv valve and fuel filter but I can't think of anything else.