Could be a number of things...
Is the smell diesel fumes or burning oil? They are very different. If you aren't sure of the difference, stand behind you car for a few seconds while it's idling, esp. when it's cold. You can smell the diesel fumes easily.
Burning oil? Hmmm... maybe a tiny drop of engine oil on a stove element!?
Explain it to the wife first, if you are going try that one!
You won't mistake diesel fumes for burning oil once you are familiar with them both.
Once we know if it's diesel fumes of burning oil, we can go from there...
