Your original post is not clear, making it very difficult to even get started on solving the problems.
Did you install a cold air intake or an intake manifold?

Did you remove, clean and reinstall your stock throttle body, or did you install a new, aftermarket throttle body?

The answer to those questions will help determine where the oil might be leaking from, and why the idle is too high.
Where did you see this oil...... front of the engine near the throttle body, or back of the engine where the intake manifold joins the rear edge of the block, or somewhere else?

 

When you accidentally "double post", it is in your own interest to "DELETE" the extra posts. Now you have two threads going on the same subject, and people responding to one thread are not getting the same info as people responding to the other thread.

I'll "merge" the two threads. In the future, when you double post, click on the "EDIT" button, then click on the "DELETE" button.