One problem related to crankcase (pcv) has been reported for the 2004 Infiniti G35. The most recently reported issues are listed below.
Engine started to smoke at start up's on my 2004 G35. Had vehicle for about a year. Took vehicle to Infiniti dealer to have problem corrected. Infinite would not repair stating that there was engine slug build up. Took vehicle to an independent mechanic to have second opinion. Mechanic found no slug build-up under oil cap nor in crankcase. I contacted Infiniti consumer affairs to stress my complaint. No satisfactions or resolution to my complaint. Infiniti has a poor warranty on their vehicles. I bought this car new and I now do all my oil changes every 3000 miles using only mobil 1 5w 30w full synthetic oil. As of this April I have had the vehicle for three years and I am now looking to trade it in and get rid of it before any other problem spring up all of a sudden. Worst warranty I have ever had to deal with. I also own a Mercedes Benz and I have never had a single problem.