No power after fuel filter housing replaced
 

I had a fuel leak for sometime. I replaced the fuel drain O-rings and found that one of the holes for the fuel drain was stripped. I took the pick up to a mechanic and he had to replace the entire fuel filter housing. When I picked up the vehicle the fuel mileage has gone down drastically and it has no power with or without a load. It has a new fuel filter, has been serviced, and a new cold air air filter.Any help would be greatly appreciated.