1995 Gas Leak or Exhaust Leak

[560Dennis]

ON Cold days of below freezing , I start up the car and it has the smell of fuel injector cleaner and when it get warmer it seem to go away. I've look around ,can't see any leaks . I'm puzzled when the source is. The defroster makes it worse ,and at traffic stops. It has a new exhaust pipe and exhaust system and I think it did it with the old one system alsoo.