Ive been having a problem with My 2006 g35 for about 1 month that when I start it up idk I can hear the exhaust sound is not the same as it was before, the car start up fine but when I start driving shortly the SES light comes on and my rpms and speed climb up slowly when I press the pedal. It's like something is putting my car in limp mode. I tried checking the code but the scanner will get no power from the car. I checked out where the obd2 port is at and you can see a connection is not connected I have no clue where it goes my car was running perfectly 2 months ago.

 

I would suggest you Service Engine Soon.

 

OP, you should get your car to the dealer or a highly respected independent tech, and have it checked out...very soon.