burn odor

In my 2001 Focus station wagon I get an odor that smells like exhaust or something burning. It was intermittant but now seems to be regular when the car is at normal operating temp.

look for any oil leaks that could be getting on the exhaust system. The front and rear seals very rarely leak on these cars but the valve cover gasket is a differant story on both the SOHC and DOHC engines.