Hi guys, I just want some confirmation before spending any money on parts or service.

My truck was running fine and all of a sudden started running like garbage in low RPM, idle was a little rough but 45mph in high gear with low RPM.. ******* and misfiring it seams.

I inspected the engine, all looked good with the exception of the air intake gasket appeares split. I took the air intake off, and sure enough it was split and wet with oil on the side with the breather hose. The intake on that side (drivers) had oil on it and going into the breather hose.

I'm no genius but think that would mean it is sucking oil up from underneath which I would assume means my plenum gasket is shot, probably causing the misfire issue.

Is there anything else it could be?

 

Leaking plenum gaskets are common. If you can be sure it's not comming from the pvc it's most likely the plenum gasket. "******* and misfiring" are another tell tail sign. Get the kit with the fel pro gaskets.
http://www.hughesengines.com/Index/p...p?partid=27091

 

If you are getting oil into the TB from the intake side of the PCV system..... (the side without the valve) couple possibilities there...... First, PCV valve is wrong flow rate, or simply clogged. Replace it with one from the dealer..... Second.... and not so good, is excessive blow-by is overwhelming the PCV system, and you are getting pressure in the crank case anyway...... Implies rings are bad.......