I just installed a bbk 62mm yesterday, had no issues whatso ever. the car felt sluggish so i figured id just re install my tune... well once i did that the car went into failsafe... so i cycled the key, disconnected the wires and re tried... still throwing a code... so i put the stock tb back on and am still throwing the code P2104 and am still in failsafe... i have no idea what to do and i need the car for school tomorrow morning.... what can i do??

 

I found this...maybe it will help:

P2104 Engine TP Actuator Cntl System
This obd2 code is very common on newer vehicles which contain new design of throttle positioner sensor. Instead of putting a tps sensor at the side of your throttle body as in older engines, a throttle actuator control system is installed which eliminates the mechanical linkage (cable) between the throttle body and the throttle pedal. Under the throttle pedal, a throttle switch is installed and a throttle module or actuator is incorporated beside the throttle body. Because there is no mechanical device that wears out, it is more effecient in delivering better mileage and performance torque (besides...the actuator module performs better in getting all throttle signals to the ecm and trany).
To test this code, check the integrity of the wires going to both the throttle body actuator and the ecm including the throttle switch. Most of the time, if you have symptoms like trany going to a limp mode, the culprit originates from the trany circuit. However, if the symptom is engine related like hesitation, the problem resides in the throttle actuator itself which may sometimes includes the replacement of the whole throttle body assembly. Contact ATS if you need a wiring diagram or detailed fixes for your throttle actuator control system.
TIP:
Before replacing the throttle control actuator and throttle body, try cleaning the throttle plates and all plug-in wiring connections. Also, watch out the throttle body mounting bolts which can easily break (use care) when removing them.

 

Remove the troublesome aftermarket Throttle Body and replace it
with the very free flowing and non-restrictive OEM Throttle Body.
Or if you must have the BBK, here are the trouble code diagnostic charts.

The Throttle Actuator Control has failed and the TAC system is
in the FMEM mode of forced idle.