I just got 2003 left over and I am still in the "baby it until you hit 500 miles" stage. Yesterday while leaving work my friend pointed out that I was spitting dark smoke out of my pipes. As I revved I could see and smell the exhaust. I drove about 1/4 mile and it went away. I should mention it was around 45 degrees. This morning from a cold start I noticed I could see and smell the exhaust but it was much lighter in color. It was much warmer perhaps high 50's. This afternoon while in the high 60's low 70's it was even lighter but to be honest it was quite windy and it was difficult to see. Basically it looks like the colder it gets the darker my exhaust. I checked oil and it looks ok. Should I worry?