My 93 has been blowing smoke out from the oil fill spout. Also when the cap is on and you pull the dip-stick it puffs there too. With the cap off and the engine revving between 15-20 when you drop the throttle it stops and sucks back in. I've found the PCV (great placement i might add!) <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> I also think i'v found where it ties into the plenum. (Kinda under the coil?) I can't tell if this is plugged as I have not removed it yet. Is it possible to shoot some carb cleaner down the tube and clean out the PCV? All this seems to be under pressure so i'm guessing no vaccum. Truck seems to be running pretty crappy at idle . Also 4x4 lights are blinking.
Any guidence or help on this?
Thanks!!! B2

Sounds like blow by, a condition where the cylinder pressure escapes passed the rings into the crankcase. Caused all sort of havoc with an old Chevy I had, didn't pass smog and horrible mileage. Do a leak down test on the cylinders, see which one or two are bad.

Definitely clean/replace the PCV. What you are describing is basically it's only function, to pull those fumes into the intake tract to be re-burned. If you have LOTS of blowby, a correctly functioning PCV might not be able to keep up, but you should certainly fix that issue first.