Engine Upper intake & Components - Carbon buildup?

[R82148V]

Hello Everyone!!

A few questions pertaining to the upper intake and connected components.
I'm doing a slow/fun rebuild/restore on my 87 Convertible. I have the upper intake off for cleaning inside and out including all the connected parts.
My question is, is some carbon buildup on the EGR valve and IAC valve normal? Also, inside the upper intake is seems to be coated with oil residue..
Just wanted to make sure this is a more thing and needs periodic cleaning or do these issues show there is a vacuum leak/s somewhere?

Thanks!!

 

[General karthief]

Usually oil in the intake is a blow by (engine wear) or intake gasket leak at the head, normally don't require periodic cleaning.
the carbon build-up at the egr valve is normal and the egr valve require cleaning.

 

[mikestang63]

oil could be blow by, bad PCV system, or gaskets
carbon buildup normal in a 30 year old car

 

[R82148V]

oil could be blow by, bad PCV system, or gaskets
carbon buildup normal in a 30 year old car

Thanks, guys!!

I'll definitely be changing the PCV valve, grommet, screen and both hoses under the upper intake.
When you talk about Gaskets. What ones are you talking about? I never had the lower intake off before and all bolts seem tight.

The upper intake runners are never too bad.. Just an oil residue I guess.. There never is "oil" meaning pooling or dipping inside the intake or coming through the TB gaskets like I've read happens to some people.
I due regularly clean the throttle plate since around the plate edge can get a little dirty so to speak.. I just chalked it up to oil fumes coming from the oil filler neck hose.

 

[KRUISR]

Yes, oil/black film around throttle blade would be oil vapor from filler neck tube.

Make sure you have or put in the screen under the PCV grommet. When I first put my car back together it didn't have the screen. At times I was sucking enough oil through the PCV valve and into the intake (hose was connected to the rear fitting in upper intake) that I was fowling the plug in cylinder #8 in about 3 hours of driving. I put a screen in and all good.