Intake Tract Gummed Up

[JDOwen2]

In the process of changing spark plugs and cables I noticed that the back side of throttle blade and intake tract from there back was coated with a black, thick gummy substance. :o I cleaned it with throttle body cleaner. Could this have been caused by a bad PCV valve? Anything else?

[SKperformance]

normal residue is black carbonm which is just a dry black soot

if it is gummy it is probably carbon and oil from an oil breather return line like that of the pcv which can stick open

[Bubbles]

It could be the exhaust gas recirculation no?

[SKperformance]

EGR runs really hot air

so it will leave a dry soot but nothing that is gummy as it would burn it up