One problem related to engine exhaust system has been reported for the 2005 Infiniti FX45. The most recently reported issues are listed below.
Excessive heat in the driver foot well. Dealership acknowledges it is 105 degrees in the foot well after only 45 minutes of drive time, but indicates it is the proximity of the exhaust system that is creating the heat - and therefore nothing they can do to fix. Actual temperature after one plus hour of drive time is unbearable, and can only be slightly lessened with use of ac (which also seems faulty) on high. Therefore, driving this vehicle for more than 45 minutes at a time is a miserable experience - but one the dealership suggests is the same as all other Fx45's.