yeah so what is a PCV Valve? Where is it located? Do they go bad? If so, what happens when they do, and how much (cost and effort) is it to replace one?

just curious thanks

If I remeber correctly the pcv valve is pretty easy to fix and its pretty cheap. Last time I had my 88LE in to the oil changed they replaced it. Was like 10 bucks or so maybe cheaper. Was pretty hard to fix on my car cause is was so dirty. I believe is recycles some air from like the exhaust or something like that. I had it replaced cause I was going from South Dakota to ohio and wanted everything done that I could get before I went. The car averaged probable 28 or 29 mpg. It has about 187k miles on it so I was really happy.

PCV stands for Positive Crankcase Ventilation.
When an engine is running, some of the combustion mix in the cylinders gets past the rings and ends up in the crankcase. That'* called 'blow-by'. In the olden days on gas tractors they used to have a little pipe sticking down from the engine that let these gases out. In the interest of cleaner air, years ago they incorporated a system where a breather tube lets air into the crankcase, and then another tube goes from the crankcase through the PCV valve back to the intake manifold. As gases escape past the rings and into the crankcase, they are mixed with the fresh air from the breather tube and sucked back into the engine and reburned.
The valve is there so the gases only go one way. If it gets plugged, it can cause problems with your idle, and it can cause oil consumption and in really bad cases, oil can be pushed back up the breather tube into the air cleaner, tho I don't know where these engines get the fresh air from.
They are easy to check, basically you shake it and listen for the ball rattling inside. If no rattle, it'* plugged. Someone said they spray WD40 up into it also, don't know about that, they're so cheap you could just replace it.
The valves are located in different places depending on the year. You'll have to get a Haynes manual and check it out.

PCV valve is very easy to replace, once u find it'* location. Should cost no more than $4.00 recommend replacemnt approx every 10-12k miles. I think it helps the oil breath maybe produces oxygen for oil or something.

ahhhhhhh thanks for the info

Um, no, there you're thinking of the EGR (Exhaust Gas Recirculation) valve. It does recirculate some exhaust back through the intake to smooth out the burning process. I know from experience that disconnecting it (on my '82 Cutlass, to see if it was actually working) will cause colossal amounts of knocking from a suddenly-richer intake charge.

The PCV valve allows a vacuum draw to pull unburnt blow-by gases up from the engine crankcase and burn them in the cylinders. Officially you're not supposed to clean it if it gets gooped up, although to be honest I've blasted mine occasionally with carb cleaner and it seems to be fine.