Try these I bought these a few months ago and I have no big complains. At first the guy at the dealer tried to tell me that they were not meant for the FX even though they are the same numbers. Maybe they just wanted me to pay $200 extra to buy an Infiniti TPMS. I paid like $140 for all four.
http://www.ebay.com/itm/New-Orange-...Accessories&hash=item256ccbe50c#ht_3234wt_922
http://www.ebay.com/itm/New-Orange-...Accessories&hash=item256ccbe50c#ht_3234wt_922