03 a4 1.8t low fuel pressure
 

I have an 03 a4 1.8t with about 160k. So for some time i've been hearing a slight whining noise while accelerating. I concluded it was the fuel pump. So I put a new fuel filter on. Nothing really changed except about a week later I start the car and hear a very strange, fairly loud whining noise. It just came and went. Not sure what it was I just carry on. The next time I start the car the same thing happens. After about 5 miles the whine comes back and the car starts sputtering. Thankfully I was close to a friends house and parked it there. I figured the fuel pump finally was out. Bought a new one, installed it and it did the exact same. Only eventually it died and wouldn't start back up. After much primitive investigation I disconnected the fuel line coming out of the fuel pump and turned the car over and very little fuel came out. It seems to me there might be an electrical issue. Like the pump isn't getting enough juice to work properly. Any suggestions on where to start? Thanks