Help - oil inside of intake chamber!!! (01 GS430)

[och]

Guy, I just started doing my tune up, my car has a little more than 100K on it. I started by removing the throttle body - and the intake chamber behind the throttle body is perfectly clean with not even a sign of carbon build up anywhere on it, but there's a very very thin coat of oil on the bottom of it. And even this oil, its perfectly clean and yellow, not like the dark colored used oil that sprays around cams.

And throttle body itself... the backplate is perfectly clean, and the "pipe" of the throttle body is covered not by hard carbon build up, but what looks to be an oily black residue. It easily wiped off with a paper towel soaked with nail polish remover. I remember when I was doing it on my LS400 I had to scrub the carbon build up from the throttle body and from the plate with a screw driver and use an obscene amount of carb removed to get it clean.

I'm at a loss. I inspected the entire engine, and I dont see any oil leaks anywhere. There's a little bit of oil residue around valve covers, close to cam gears, but nothing alarming at all. Also, the car does not seem to burn or consume oil at all. I only put mobil 1 synthetic oil and change it every 2000 miles.

I'm at a loss here. Any ideas guys?

 

[is_250]

Im thinking the oil probably comes from the PCV? It recirculates the crankcase pressure back into the intake.

might be time to change your pcv valve.