I have a 2003 G35 sedan, I have had it for 2 1/2 years now and about a month ago it started turning off. It use to only turn off after it had been running and the engine was at the regular temperature. But lately it has been trying to turn of when OI'm trying to warm up the car. Any ideas why this is happening? I have checked the engine oil and it is normal. Could it be the transmission oil? Please help!!!