Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hey there, thanks for the question.
If your getting the smell of fuel through the vents then it is more than likely coming from one of 2 places. Either you have an exhaust manifold leak or a slow fuel line leak by the intake manifold.
Let me know how else i can help please.
If the smell was from the tank it would be consistent.
Your getting the smell through the vents because of the airflow change from driving at high speeds to coming to a stop and its coming through the vents likely because your not on recirculate but instead using outside air. If that's the case I can't think of anywhere else it would come from.
and you never mentioned your mechanic looking at the exhaust manifold.
the exhaust manifold leak would allow unburnt fuel and gas to escape BEFORE the catalyst. It would smell no different than raw fuel.
and there are no fuel or evap lines that travel inside the cab of the vehicle EXCEPT the access for the fuel pump in the gas tank under the rear seat.
its really where the rubber lines connect at the damper/rail they will leak when the engine is cold and slowly drip into the manifold valley and you will never see the leak, just smell it.
if the dampers themselves were failing they would generally make a knocking noise and it sounds like your driving a diesel engine.