Anything you do such as pulling a pipe off that is conencted to the inlet will allow more air in and of course cause higher speed of engine, it doesn't get it's main air suply from here so not an issue.
The PCV breather system on the block should have a one way valve in it, so that it cannot draw on it at idle, only at higher revs where it is ingested into the engine, this also adds a little restriction as it is a smaller diametre than the pipes, so I'd check this first, a very small amount of oil is not unusual if ragged to death ?
tabetha