I have a tiny bit of oil coming out of the prc tbu hose in this pic. http://shbox.com/1/map.jpg

What does that hose do? What does it mean? Is it emission related or something?

 

That's the fresh air supply from the throttle body to engine for the PCV system. It is not uncommon for some oil to migrate back toward the throttle body on high mileage engines or ones that see a lot of high RPM use. Make sure your PCV system is operational and the valve is not clogged.

 

It's part of the PCV system, it's supposed to help pull any blow by or other positive crank case pressure out.

I would try cleaning the pipe/TB and changing the PCV valve.

 

http://shbox.com/1/map.jpg

Question- This hose that goes from the TB to the valve cover on the passenger side being discussed here: If I do away with that hose, put a breather on the valve cover and cap the fitting on the throttle body, but leave the PCV hose and valve connected on the drivers side TB to manifold, could it cause vacuum problems?

 

Nope. That's how I run my system after blowing the dipstick out of the block at 8 psi from an S trim.

 

Nice.

Oh well, I guess that would have been too easy of a fix for my low vacuum at idle, had to ask though!

 

Yeah, nothing like burning the tires in 3rd gear and having white smoke come pouring out from under the hood. Talk about a moment. Luckily nothing was hurt, just a nice oily mess everywhere.

Are you talking about a low MAP reading? Removing the hose probably won't fix that.

 

I'm trying to chase down a problem where the MAP sensor is not seeing enough vacuum in the manifold at idle. I thought perhaps me removing the crankcase to TB vent hose on the passenger side, while still leaving the PCV setup on the drivers side was letting air into the manifold from the crankcase, therefore leaving me with the low vacuum problem.

My cam is pretty big, most of the problem has to do with that.

 

It will cause the small amount of air that is drawn by the PCV system to not be accounted for by the computer (because you are drawing the air from the atmosphere and not through the air in the throttle body that has already been measured by the MAF). The computer can, however, compensate by virtue of fuel trims based on O2 readings.
Injuneer has explained this at length many times, if you can find an old post.

Breathers are necessary on blown cars because of the extra associated crankcase pressure.

 

Simple enough to cap off the vaccum supply to the PCV and see if anything changes.

 

Thanks for your help. I can going to clean out the hose, tb and change the pcv. Hopefully that will get rid of that. The car does have a 104,000 on it.