STOPPED DO TO HEAVY TRAFFIC AND STARTED SMELLING EXHAUST IN CAB. PULLED OFF ON NEXT EXIST OPENED HOOD AND DRIVERS SIDE OF ENGINE WAS SMOKING. COUGHING AND LUNG DISCOMFORT. FOUND SOME SHADE TO LET TRUCK COOL. NOTICED BLACK COLOR ON REAR OF EXHAUST MANIFOLD, LOOKED CLOSER AND MISSING BOLT IN SAME AREA OF MANIFOLD. LOOKING ONLINE LOTS OF COMPLAINTS OF SAME PROBLEM BUT NO RECALLS. SHOULD BE EMISSIONS RECALL AND SAFETY RECALL IN MY CASE. *TR