The fuel tank issue is inexcuseable. The fuel module could leak. I wonder if this is an inhouse build-up job or if the tank comes in from the supplier with this module installed? Since it is across vehicles built in at least 3 different plants I would suspect a supplier issue. If it was on an in-house build-up job there would be just one worker who was doing something incorrectly, or their tooling wasn't working right. But since it is on vehicles built in at least 3 different plants it would seem to be a supplier issue.