Hi, and thanks for your medical question on eHealth's Ask a Doctor forum.
The symptoms of smelling an exhaust like smell everyday could be due to the smell getting trapped in the nasal passages due to polyps, inflamed nasal turbinates, foreign body or due to tumors.
In these conditions at times the air carrying this smell (you may have felt it somewhere) gets trapped causing one to smell it again and again. It could also be due to fungus in the nasal passage.
It could also have a psychological component to it. Since a confirmed diagnosis cannot be given on net please discuss these possibilities with your doctor once. You may need to consult an ENT specialist. Hope this helps. Take care!