Your Mustang must be a Cobra, Right Otherwise how could it benefit from Snake Oil?I have nitrogen in my Mustang and in two years I have not had it add any air or nitrogen.
I also had nitrogen in my Explorer Sport same thing.
On both those vehicles the dealer purged the factory air and serviced with the nitrogen.
When I took delivery of my Ranger I asked if it too was serviced with Nitrogen in the tires and they said that they only do Nitrogen in performance vehicles (Mustang and RX Sport).
I have had to adjust the tire pressure twice in 4 weeks on the Ranger, granted I have only added a total of two pounds but still...
BTW my tires were properly serviced by the dealer during "prep."
I am seriously considering a Nitrogen purge and fill on the Ranger...
Just kidding ..really.