2010 Honda Fit 4 cyl Two Wheel Drive Automatic 4,200 miles
I recently bought a new honda fit. I drove it for around 4 months before getting an oil change but before I got the oil change it suddenly started to smell like burnt plastic randomly when I drove to work and when I turned on the vents but then would disappear. After the oil change it still smelled like burnt plastic and they said that my car was fine.
Check your exhaust system. Note if any foreign materials are stuck to any part of it. Exhaust gets hot while running and plastic bags or sheets would stick to it. This would result in intermittent burnt plastic smell.