Unexplained Limp Mode

EZT

Hello everyone,

Just a few bits of general information about my Z first.
2009 Base 7 AT
208k miles
Just had valve covers, gaskets, spark plugs, oil change and transmission flush performed at local dealer.

Car has driven great for my 10 years of ownership, with a few blips here and there, but nothing even remotely serious.

At any rate, I started it up this morning, thought the exhaust note sounded very odd at cranking it, and upon attempting to accelerate the car took seemingly forever to climb up in RPMs, even with the pedal to the floor. I’ve never experienced this. No SES light or anything just unexplained limp mode. I had it towed to Nissan where they were finally able to create it, I guess it took them half the day to have it happen. They suspect the ECU, but some tertiary reading points to cleaning TBs, MAFs, or the brake pedal thing which I cannot remember for the life of me what it’s called.

Anyone else have further input or direction? Nissan said they’d contact me in the morning with their complete diagnosis.