Hi everyone, I have a problem with my vehicle I just noticed few minutes ago, it's Sunday night and I don't want to disturb my mechanic, so I came straight to you guys.

I have an 02 Audi A4 18.t quattro sitting in my garage at maybe -5 that will not start, seems like the car is dead gone.

First when I go to start the car I notice that rear lights were on (I did not leave the switch on), and I try to unlock the car electronically and it won't. I go grab my spare and still the same thing, so I unlocked it manually. I get in and put the key in and turn it only half way, rpm and speed gauges, the temperature and all the buttons in that panel that usually light up did not, with the exeptions of the esp, engine light, and all the lights in that area. I go all the way to try to start it and nothing, no crank, no noise, won't even try.

Any knowledge-based replies will be highly appreciated. Please no guesses, so I won't waste my time researching unimportant matters.

Thank you

Edit***

I got a battery charger and charged it for 15 min and it worked, so I let it sit for 5 min and took it for a drive. I was going about 40-50kmh and I noticed power loss, my foot was at the same point on the gas pedal but it would lose power so I'd lift my foot up for a second and press back. It did that 3-4 times; then when the temperature level was close to half it stoped doing it and drove normal.

What do you guys think?

I was thinking maybe fuel pump or injectors?