The Goo Goo Dolls’ show Tuesday at Musikfest’s main Steel Stage in South Bethlehem wasn’t perfect. It wasn’t even as good as the group’s show at Reading’s Performing Arts Center in November.But there still was enough in the 19-song show, which lasted just short of 80 minutes, to make it very good, with some highlights that hit the heights of the group’s previous shows.The biggest fault was inconsistency: After the group started with oomph on “Sweetest Lie,” singer Johnny Rzeznik’s voice faulted slightly on “Slide,” and there apparently were sound issues, as well – Rzeznik exchanged acoustic gu