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The best way to trace the problem you are having( P0442 small leak detected) in most cases is you are going to need to have your Explorer hooked up to a smoke machine. Before doing that In many cases this code is set due to a loose gas cap and before I would do anything else , I would makes sure the gas cap is installed tightly and then remove the positive battery cable and reset the PCM. Drive the Explorer and see if the code returns. If the code returns then you will need to run the pinpoint test.
Ok if the light is returning then you have a small leak in the EVAP system, the best method for finding it is with a smoke machine . I am enclosing the pinpoint test. Its for )442 and 443