I have a 2003 lb7 with a new intake and a 5 inch exhaust. The truck has 167,000 miles on it and started smoking white. When sitting at a red light it smokes a little then on acceleration it comes out more then goes away when at speed. I read some threads and they said it just be cold weather. Its around 25 degrees during the day. It didnt smoke during the summer or fall just winter.