Removed the cover from the left tank and found very poor proseal application in the both the upper (photo 2) and lower (photo 3) corners. Material was not even smoothed out and was full of holes. Photo number 1 shows where I removed the "blob" and indicates poor adhesion to the metal. This is where the illusive leak was coming from.
Van's Aircraft helped me with this and we were finally able to get it resolved. Thank you, Scott.
