The PCV is on the rear valve cover, more on the passenger side of the engine. We have a 2002 Avalon and LOVE it! Check the dipstick for heavy varnish stains which would be indicative of long oil change intervals. In addition I would wipe my finger in the tailpipe, if your finger returns with alot of black soot, then chances are it burns oil which could indicate sludge problems. Our Avalon's tailpipe is very clean and the engine doesn't consume any oil. Ask the owner if he used a synthetic oil in it. This is an engine I would not run anything but a synthetic. You may want to run a carfax to confirm no prior issues(accidents, TSBs, etc.) If the car returns alot of white smoke upon start-up that is a sign of sludge. Finally, take a flashlight and peer best you can into the oil fill hole. You can see alittle if you put your line of sight at about a 30-40 degree angle to the fill hole. That V-6 is the smoothest engine I have ever driven; in fact we returned 31 mpg on a trip to Houston. Amazing cars! Best of luck and keep us posted.
