Won't crank/Gas smell and leak

What is your question?

Recently I had my engine replaced. But before that when I was driving her she would idle down and shut off at a red light or a stop. I would have to keep my foot on the gas slightly so she would shut off. She would crank back up with no problem. During this there was a strong gas smell. I was told she needed a tune up and I did. Still same problem. Was told that it was the fuel filter and had that changed but when they changed it there was wear and tear on the small L shape hose that connects from the line to the fuel pump and I went to get it at the auto part store and they did not carry it but recommended the same size hose but not L shape and also recommended this spiral wire so they could bend the tube with out it collapsing. Well needles to say that when I got back to the jeep the wire thing was a damn to get on and when he did manage to get it on it wouldn't fit right so it was a waste. They hose is on there with the wire but the wire is not doing what it is suppose to do and the jeep won't crank right away. It hesitates, stronger smell of gas leaks gas sometimes from the fuel filter area after the third or forth try to start I wait about 5 minutes they she cranks. But today she didn't crank at all she back fired and scared the crap out of me. Can anyone give me advice?