So I've been having problems with my G. I've already changed out the map sensors, and o2 sensors. I've also cleaned the throttle body and done a throttle reset and ecu reset.
my problem started with me putting the car into sport shift/slap shift and it not wanting to shift properly. Then started to have a cylinder misfire. It just started dying after starting it, and when I get it to stay running it idles at about 1100rpm, and won't rev past 2500 rpm and sounds like I hit the rev limiter... Any suggestions?

 

Get a scanner on it first. I got errors to do with cams. Does it die from start or only when put into gear? I babied my 2011 G37x but I've put a transmission and Engine in the past two years. Drives like a champ again and to be fair I put 270K km on the engine before a seized piston bearing. Oil changes synthetic only every 5K Km. The transmission only gave me 160K Km. Unfortunately she was used, so it's hard to say what she went through in the first 80K before I bought it. When my transmission went it did the same as you but only when I put it into drive. When my engine went it slipped on shift during driving and pulled hard like I was hit from behind. Then sounded like a thrown rod when I tried to start it.

 

Mine does the same. When it shifts it shifts hard. It would die when stsrted, if I got it running it would die after I accelerated it when the rpm would go down. It hasn't died today, but it runs rough and shifts hard wheels breaking loose

 

Hopefully I won't have to replace motor