Fordmustang04

I had an accident on my mustang I had broke an axle then fix it 2 days later check fuel cap came on then check engine light with p0457 so I replaced the fuel cap and erased the code it's been 2 days and my check engine light just came on with p0455 gross leak not sure car could it be it's pretty expensive to do a smoke test at the dealer I heard its around 240 any halo what I could do or what it is ? Thanks