Posible causes of epc light on my A3 fsi 2.0 2004 it doesnt have power

If U don`t have VAGcom to read and erase the errors try first the brake switch if its ok (sometimes the brake lights remain turned on even if the brake pedal is released and this cause the epc light on).
If you see a engine speed decrease when epc turns on the error could be from admision *(air intake) pressure sensor . You can disconnect your battery minus*(ground) for 10 or more minutes to turn off the epc light but if you don`t resolve the problem epc will turn on again when U start the engine. My advice is to find a Diagnose cable and read the error to know exactly what is the problem

Most likely if you have the model that is drive by wire aka electronic throttle body the 9 times out of 10 your gas peddle is on it last legs replacing it will most likely solve your issue with epc light comming on

"Engineering, Procurement, and Construction" (EPC) is a particular form of contracting arrangement used in some industries where the EPC Contractor is made responsible for all the activities from design, procurement, construction, to commissioning and handover of the project to the End-User or Owner.

In case of cars:
The EPC indicator is a standard in Volkswagen and Audi models. These vehicles have drive-by-wire systems that are computer-controlled. When a fault exists with the throttle pedal, throttle body, traction control and cruise control, the EPC warning light illuminates. In many instances, the vehicle's throttle may be limited when this light is illuminated in order to protect the engine. Often, there is just enough power enough to get the vehicle to a service facility for repairs.
http://electronicshelponline.blogspot.com/

Go to a store like autozone and get an obd reader to check the codes, use the "loan a tool program"

First check the fluid level and make sure it is correct. If it's good you will then need to go to the dealership to have the codes pulled. I hope the problem is the fluid because it will be expensive otherwise.

That is the throttle control. It is an electronic part that changes position when you step on the gas pedal. Replace it.

First of all you need to access the Engine Control Module (ECM) using suitable diagnostic equipment connected to the data link connector of the car, in order to pull out all DTC's memored. DTC = Diagnostic Trouble Code. Then you will bu full informed about the root cause of the problem, and you will be able to repair & replace bad pieces and reset the ECM. Then both EPC (Electronic Pedal Control) & engine warning yellow light will turn OFF.

I am having the same problem on my Audi A4 2004 FSI, lose power whilst driving at speed with the EPC light coming on. Looks like a design fault of some kind with Audi petrol engins, have read a few forums about this but no clear straight answer. Check the link below:

http://www.audi-forums.com/b6-forum/37371-a4-fsi-epc-light-power-loss.html

Have you verified that the power steering fluid is at the right level? If it isn't, you need to fill it to the proper level using specific Audi power steering fluid (it's a mineral-oil-like fluid, NOT the stuff you buy at the parts store). If you've run the reservoir dry and kept driving, it's likely you've burned out the pump and will have to replace it.

Yes according to the dealer they are the same heads..