Some oil in the throttle body is normal, it depends on how much there is.
It also depends on how the throttle body is set up, on a vertical throttle body or carb your not going to see nearly as much oil because more will drain down into the plenum/ manifold. It also depends on where the PCV hose enters the plenum/ manifold( most enter right next to the throttle body , some at the other end of the plenum/ manifold).
Your fouled plug may or may not have anything to do with the oil in your throttle body. Puffing blue smoke on start up usually points to bad valve stem seals, you would probably be seeing it on deceleration also( from valve seals).
Are you burning alot of oil ? How many miles on your engine?
A bad PCV valve can cause you to suck more oil into you intake, also over filling with oil.
If your engine is high milage then rings, valve stem seals and blow by will cause you to burn more oil.
You can burn alot of oil and never see if you have a good CAT.
Last edited by sam333; 02-12-2011 at 11:00 PM.