Oil or exhaust smell in cabin

Check that your spark plugs are snugged up to the correct torque. If they are ok, can you find any leaks in the manifold or exhaust?

 

VERY DANGEROUS TO YOUR HEALTH.

I have seen this complaint a few times with no poster resolution post. I do know the donut connection at the end of the exhaust manifold where it connects to the main exhaust runs gets loose over time. Once when i was cleaning the ecoil under dash I checked it and it was very loose.

If your not handy bring it to a muffler shop and let them examine the entire exhaust system thats cheap.

In the meantime go to youtube and look up

Prius inspection mode

it will show you how to put the engine in inspection mode and the engine will idle endlessly until you shut the car off.
Do it at night and while engine running get under the car in the rear sides and look for smoke with a good flashlight.
Easier to see at night.

 

Another possibility: check that oil fill cap is on.

Don't ask how I know about this one...

 

lol...yes its happened to all of us...