Inexplicable loss of power in my 370Z

[Z Ninja]

I have an inexplicable loss of power issue with my 2014 370Z. I pulled out of the parking lot from work and immediately noticed I'm being limited on my power. I could shift into 2nd gear and put the accelerator all the way to the floor and not get much past 3,000 RPM. No engine warning lights or anything on the cluster. Idles fine, runs smoothly. I stopped for groceries, started the car up again, problem disappeared. I took it to the dealer and they charged for diagnostics and said they couldn't get the problem to repeat, but had a single failure of the brake switch. They replaced the brake switch, under warranty, minus $100 deductible. Apparently the theory is the brake switch limits the engine if it detects you're on the brake while trying to accelerate.

First couple of times driving it, no problems. As soon as I pulled out of the parking lot from work, same thing again! I pulled over, shut the engine down, started it back up, problem gone.

What can I look for? I've read similar articles online suggesting dirty MAF sensor, maybe engine computer has a bad grounding problem. Another suggested disconnecting the battery to reset everything.

Does anyone have more ideas? I don't want to continue to be charged diagnostic fees and have them find nothing and unable to repeat the problem.