I have a 2010 G37S sedan with around 11000 miles on it, only modifications are K&N Typhoon intake and a subwoofer. Tonight it was driven pretty hard for a few minutes then I felt a lacking of power. Feeling this lack of power I decided to put it under wide open throttle, it got to 120mph in 5th gear and cut out, went down as if it was a speed limiter then went back to 120mph and cut out again. I pulled over and shut the car off thinking it some how went in to limp mode, went back on the road and it exceeded 120mph, although still under extreme power loss. No check engine light. Going around highway speed corners at a little bit of an excessive speed it feels as though it is lacking the stability it usually does. When taking corners at a little bit of an excessive speed, still under throttle, VDC and slip seem like they are going overkill. Normally it just cuts a little, but still maintains momentum. I am completely lost and a bit concerned as there is no check engine light on and feels like there is some sort of system error if it is effecting power, VDC, and slip. Any ideas?

 

I was thinking it was a possible slipping clutch and it was slipping then cutting to protect over slippage, but with the no clutch smell, no actual slipping in any gear, consistent but lacking climb in rpm and mph, mileage, vehicle not being beat on rediculously, knowing how to drive stick, and the other symtoms I ruled that out.

 

^agreed. Do you notice any smells at all? I would say maybe try resetting your ECU.

 

Bad gas? Do you always use 91?

 

I always use 92 or 93, searching around I was kind of debating bad gas too. Would that cause the overkill with the VDC and slip? I know it would not explain the highway speed feel of loss of performance, which may just be me being overly paranoid with the power loss and overkill VDC and slip issues.

 

No smells, after parking I smelled the front and rear fender wells, no abnormal scents. I also did not smell anything coming in to the cabin while having the issues either. I will see on the return trip, may try running it dry of gas and going to a different gas station and hoping that was the issue.

 

Did you oil the K&N filters or are they dry filters? If oiled, there is the possibility that traces of that oil have blown up your intake pipes and have gotten your MAF's dirty, and causing them read rich (or lean). I don't know about the VDC acting strange though.

 

First post.

After digging, this was the first thing I found that was close enough to this strange problem I have been hitting.

Had a Saab...decided it got too old (parts are kind of hard to find ) and bought a 2011 G37X about a year ago. G/F drives it mostly. We chose it because it drives pretty easy, but I can take it out by myself and have a ball.
Okay - I put the stock paddle shifts in because it does not have them. Each time this happens, I am shifting in manual mode (A7T in the car), but that may not be related because I am also going to be shifting that way when driving hard.
I will drive it spiritedly for about 20-35 minutes in order to hit these passes a good bit away from home. The entrance to the switchbacks is a sweeping 360 degree corner that grades down under the entrance highway as you take it.
I usually hit this pretty hard (with VDS on each time this has happened, I usually drop it off later, but not for daily driving and this is still just spirited driving)
I will hit it around 40-60 mph depending on if I am entering or setting the corner or pulling back out. Usually in 4th, near 5.8 to 6.5 rpm through the entire corner.
Pulling out, flooring it, the VDS is kicking in at this point, and shifting to 5th and BOOM
My freaking rpms start falling. Car will NOT go.
If I gently press the gas it will pick up speed, but if I go more then, (estimation) 50% on the throttle, it will give the feeling of losing speed. I believe this is a "limp" mode I read about so much on the forms. After ohh...60-150 seconds, I can punch it again.

what. the. heck. is. wrong. with. my. car.

Disclosures : It may have happened once before when i first got it and drove it pretty hard for a bit. I vaguley remember but I could be wrong about that.
Doesnt seem to happen anywhere else. Just this stupid long sweeping corner.
I dont drive it, after this experience, really hard through the switchbacks because power dropping out with VDS off through a corner could drop me off the road. I cannot trust the car.
Anyone got an idea where to start looking?

 

maybe just try to reset the ecu?