That's a huge leak that should be easy to spot. Most likely a fuel hose. It should be replaced only with a hose marked "SAE 30R9" or "SAE 100R6". Hose with a rating of 30R6 or 30R7 is not rated high enough for the pressure of the supply side. Hose is about $3 a foot and if you are handy you could do the labor yourself, using new fuel injection band clamps. Hard to guess what a pro would charge, maybe $100 parts and labor.