Well, I have had my G35C for about 3 months now and it has ran wonderfully up until now. About 3 days ago it started with these problems. The problem is, when I am driving and I push the pedal down to accelerate, I will hold the pedal in the same spot but it revs up to 4k then drops down to 3k. It does this in 6th gear mostly but it has happened in 3rd, 4th, and 5th also. Has anyone had this problem or does anyone know what is wrong?

 

It might be your Throtle Position Sensor (TPS). There has been some problems with them, so just go to the dealer and get it replaced.