A loose gas cap will cause a P0455 code.

If that hose is off the DPFE sensor and there is not good reason for it to be off, you may have plugged cats and the backpressure blew the hose off.

If you were within your 8/80 warranty (7/70 in CA), you'd have been covered. Bummer.

Steve

98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!