We purchased a 2003 390 XL Skydeck in April of 2015. We love it and it is great unit, but on our trip home which took us a week we soon realized there was a issue with black tank odor filling the MH whenever we flushed the toilet or even moved the MH. After we made it home I checked everywhere and could not find the location of the leak. Finally I removed the washer/dryer and had to cut open wall that was between it and the refridge and alas the culprit was revealed. The vent that comes up from the curbside of black tank and goes through the floor and ties in to the vent for the grey tank which is between wall panels. The elbow had pulled loose from the connection and was now just venting into the interior of MH. This must have been an issue for quite some time because the pipe had never been glued together from the factory and must have vibrated loose. Was an easy fix once found.