Golang, FZF picks only first line, problem with logic?

I'm using fzf to select objects in a list, so i thought of passing the STDIN of Formcars(),and passed it to fzf as a buffer.

code:

func Formcars() {

..... //some code

for _, res := range resp.Automobiles {
            ..... // some code
            continue
        }

        for _, car := range res.Types {
            ..... // some code
                continue
            }

            cars = []string{
                *car.Engine
                *car.Type,
                *car.Date,
                *car.Reg,
            }

            fmt.Println(strings.Join(cars, " | "))
        }
    }
}

func Filter() string {

    stdout := os.Stdout
    r, w, _ := os.Pipe()
    os.Stdout = w

    Formcars()

    ChnOut := make(chan string)

    go func() {
        var buf bytes.Buffer
        io.Copy(&buf, r)
        ChnOut <- buf.String()
    }()

    w.Close()
    os.Stdout = stdout
    str := <-ChnOut

    cmd := exec.Command("fzf", "--multi")

    out := bytes.NewBufferString(str)

    cmd.Stdin = out
    cmd.Stderr = os.Stderr

    if err := cmd.Run(); err != nil {
        fmt.Println(err.Error())
    }

    return strings.Join(cars, " | ")
}

func main() {
    str := strings.Split(Filter(), " | ")

    fmt.Println(str[0], str[1], str[2]) //for debugging purpose
}

If i select a line in the fuzzy list it ignores that and chooses just first one, must be a wrong logic but can't figure out what's wrong