weird smell from under hood

Just picked up a '99 VW Beetle 1.8T, and been driving it the last 2 days and i've noticed a light "rubber burning" smell coming from under the hood. I took the plastic cover off of the motor and can't seem to pin-point where it is coming from. Anyone have any idea what i can check? Other than the smell, it's running, shifting, driving just fine. I checked all the fluids, which look good, the oil is a little dark, but i'll be getting an oil change tomorrow...

Sometimes people don't use a funnel when putting oil in the engine, and because of the akward spot the fill area is in, you could spill some down the back across a hot exhaust manifold. See if goes away in a couple days.

if its a rubber burning smell maybe its the timing belt or serpentine belt. If the timing belt was replaced recently the metal middle or lower cover may be rubbing on the belt.

Smell disappeared yesterday, but then i smelled it again today...kind of just ignored it, and then when i pulled into my driveway tonight a "Check" light came on the dashboard, and i looked it up in my book and it says something about "MLI" or something about needing to have my ODBII codes run to see what the problem is. Will the codes that are pulled give me a pretty clear understanding of what the problem is? Also, can i take my Dub to any autozone or advanced auto parts for a free scan? Thanks!