I suspect the small amount of oil you are seeing in the passenger side air duct (#13) is coming from the passenger side rocker cover vent line (C) in the diagram below:Hi Folks,
In the midst of changing all the fluids on my car yesterday (both diffs, xfer case, transmission) I decided to peak down into the air intake ducts.
Bad news. I see oil in the RH passenger side air duct at the bottom where the bellow is. It's not a lot, but it's enough to appear a little bit damp. The LH side is bone dry for comparison.
To add to this issue, the last time I changed air filters about 15,000 miles back, I didn't realize but the previous air filter gasket had gotten pinched with a kink. I'm in dusty, disgusting northeast AZ with lots of blowing dust and sand so there was definitely some dirt that had gotten into the intake duct.
So what I'm seeing is a little bit of congealed dirt and oil at the bottom of the bellow. Not puddled, but definitely "wet" appearing.
As far as any issues - none. No noises, no exhaust smoke, good fuel economy and good power. I get a real frequent failsafe mode where it limits power under 3000rpm (topic for another thread maybe) that clears as soon as I turn the car off and back on again. Otherwise, no odd noises or power loss. I don't hear turbos whistling or whining. OCI has been 5-6K miles with good oil analysis reports. I've extended OCI to about 9K miles a few times and oil level has never dropped - not using oil.
How effed am I? To beat it all, I'm at 71K miles, so bye bye warranty.
The passenger side blow-by hose (#4) in this diagram below shows where "C" in the previous diagram is connected to the rocker cover:
I don't think it's anything to be concerned about.
As far as your limp mode issue, if you have an OBDII scanner and this happens again, you might try scanning the car for DTCs before turning off the ignition. Temporary DTCs will typically clear on ignition cycling.