I got the same exact problem, happened to me once a couple of months ago, and again last night. I was driving the car and tried to give it a little gas, started bucking. Would go above ~2000rpm even with slow acceleration. Parked the car and restarted it and it went away. I'm 6mt so I'm guessing this problem isn't related to your AT transmission. I also have stillen intakes, and wondering if it could be the MAFs. I'm going to check the wires with a voltmeters and see if it's always sending signals even if they're being wiggled a bit. asked my friend that works at nissan if they've ever had a 370z come in for that, and he said nope.
p.s. first time it happened a simple shut the car off and restart didn't work... had to lug it home ( i was only down the street) took my batt clamp off and replugged in the mafs. worked after that though.

 

The same issue happened to me on a bone stock 07' G35S 6MT Sedan. It would usually happen 5min after driving. I thought it was the synthetic oil/ambient temperature/whatever else I can think of, but it went away when I started driving the car more aggresively. Which makes me wonder, would the problem go away if you reset the ECU?

I don't have the car anymore...

 

Very interesting...

Until I read the posts from the 6MT drivers... I was convinced (for no dedicated reasons) that this was a tranny issue that causes the engine to do something weird...

Wouldn't a MAF issue give a check engine light? I guess not all errors can be monitored by the computer.

Well, had the tranny reprogram (TCU) a couple weeks ago, and so far .. knock on wood.. tranny shifting is apparently smoother.

 

Actually questioning the MAF brings up a very good point

On my old car (01 i30, and the same gen Maxima) a bad MAF would make the car not clear a certain RPM, and back then the MAF did not trigger CEL AFAIK.

Couple that with the fact that it seems to be happening with moisture on the road/ground, it makes me wonder if the engine ingested a little water that then "polluted" the MAF. Couple THAT with the fact that it seems to work again 30 minutes later (i.e. after the water drips, dries, or evaporates off the MAF), it really DOES seem like a possible MAF issue.

Do you have a scanner that can read the sensor data? If it happens again and you can somehow see what the MAF is reading, it might be a big clue.