Hey, I'm pretty new here, this is my first post. So I recently just upgraded and purchased a 07 G35x from the auction It's pretty clean, only one owner and just 160k kilometers. Car is great and a huge upgrade from my 03 DE sedan, but I've noticed a weird random issue that I need help with. Around 40-60 whenever I try to hold my speed in D the car starts rubberbanding/sputtering. Whenever this happens the RPMs will drop 100-250 and bounce back up constantly, also the problem doesn't seem to happen in DS or M mode. I'm not sure if this would be a issue with the trans,plugs,throttle body or maybe the fueling. But it pulls hard and is perfect under WOT. The car throws one code: P0455 Evap Emission Leak which is the same code I bought my DE with lol.

 

First I'd pull and inspect the plugs, gives you a good chance to give everything a once over.

As for the EVAP code, find the leak, fix it, this car NEEDS it's EVAP system functional or it misbehaves.