You need someone to look for the cause. We can't do that over a computer. A little oil on the engine can smell like something burning once the engine warms up. If it's something electrical you should see smoke too or a battery cable will be hot. Wire harnesses have been known to fall down onto hot exhaust parts, then the wires short out. You may be getting more warning of an impending serious problem than most people get. It might be something minor, but why risk it?