If your intake gasket is sucking
oil into the intake manifold, or the cylinder, then I would suggest that the intake gasket needs to be replaced. Exhaust gases getting sucked in due to negative pressure is one thing, but
oil should not get sucked in to the manifold. That is a gasket issue. Unless of course you are creating so much negative pressure that you are sucking
oil past the piston rings and all the way up into the manifold
, not likely.
I suppose one other potential reason would be that oil is being sucked up through the pcv system and then back down into the manifold (I am not very familiar with the all of the functions of a throttle body system), but again, the intake manifold gasket seems the most likely.