i was doing my oil change today when i notice some black stuff on the intake plenum looks like dry oil but its on the very top of the engine! any ideas where it could be coming from??

 

Could be remnants of a failed AOS. Oil can collect in the throttle body and plenum then leak out the rubber hoses between the plenum and intakes. Try removing the oil cap while the engine is running. If the AOS is going or bad it will create a large vacuum making the oil cap removal difficult.

Another test is to remove the throttle body and look inside the intake plenum. There could be some oil sitting in there. It's not too difficult to do but does require a reverse torx socket (etorx or female torx, two of the bolts are visible on the TB in the photo). Pull the airbox then unscrew four bolts on the TB. If possible keep the electrical connector to the TB connected so that no TB calibrations are needed. Or disconnect the battery before disconnecting the TB. With the TB out there is a better view of what's under the plenum.

 

car doesnt smoke at all.. but ill try that and see if the aos is going bad wouldnt it smoke alot?

 

i try to open the oil cap and there was no strong vac!! if anything car sounded like it wanted to stall when i did that but oil cap came off without any hesitation!

 

Normal. They all do it to some extent. Some oil will make it past even a fully functioning AOS over time, and get worse as the diaphragm wears. Don't sweat it.

 

ok thanks no smoke no excess vac so ill just clean it n forget it..