How many Fuel Lines under car, 2 or 3?
 

I have a 2000 Volvo S80 2.9 (non-turbo) The guy who worked on it before me didn't know what he was doing. I changed the fuel tank and the car I got the tank from at the bone yard had three gas lines running from the front of the car to the rear. I hooked up the two main hoses and the car run but sometimes feel like it is no getting enought gas. Is the third line for gas ventilation or does anybody have a diagram of wher the lines go?