I'm actually having the same problem, temps dropping and my warning light keeps going off. As far as Nitrogen goes your only bet would be the dealer. I think they charge a one time fee of 30$ or so for a lifetime fill up of Nitrogen anytime.
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|2013 Audi S4|Ibis White/Black|S-Tronic P+|
|2013 370z|PearlWhite/Persimmon|Touring/Sport/Nav|F.I. CBE 18" CF|
|Sold|2011 370z|Gun Metallic|Touring/Sport/Nav|
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