I have 2009 g37 Sport Coupe with 79k miles and I have never had a problem with my car until recently. I been having problems with my car sputtering and barely accelerating then eventually cutting off .This is only happening during the winter months and it starts in the morning just fine.I let it warm up in the morning while I getting ready for work and it drives fine on stop and go street driving. But when I get on the highway it starts sputtering and won't let me accelerate pass a certain speed. No lights on the dash board came on so I was confused. This scared the **** out of me because it just dropped speed and starting sputtering on a fast highway. I was lucky this time cause I was still in the entry merge lane onto the expressway and was able to hit my hazardous lights and pull to the shoulder. After sitting for awhile every-time I would accelerate it would sputter and cut off. I soon realized that the car would accelerate but not fast enough to get back in moving traffic. I managed to drifted on the shoulder to the next exit to a gas station and filled up my tank because I was under half tank.After my car drove just fine.The first time this happened was in December during a random week of freezing cold temperatures in the low teens.
I thought the problem was solved because It drove fine up til this point. But It happened again the exact same way. It drives fine until I get on expressway. I had about a half tank of gas and the temperature was 27 degrees. I'm in Maryland and this is normal temperature for my State around this time of year and my car have been through worst winters then this with no problem. I need some answers cause the dealer looked at my car and said they didn't see anything wrong. Can somebody let me know if they had this problem and what they do to fix it

 

The float in the gas tank could be stuck which would cause your gas gauge to read incorrectly. If your car drove fine after filling it up that would be my guess. Does your gauge ever go under half empty?

 

Yep that's exactly what it sounds like. How many MILES are you driving on each tank of gas. Your fuel level sender of combination meter could have gone out and when it's reading 1/2 tank you actually have just ran out of gas.

Sputtering and lack of power leading to stalling with NO SERVICE ENGINE LIGHT usually means you just ran out of gas.