NASCAR suspends 4 crew chiefs; Waltrip's status in doubt

I don't get this story. What did these chiefs do? 2 of them apparently had open air vents where they weren't supposed to be but how bad is that? And what's up with the other 2? And what's up with Waltrip putting sterno in his car--why the hell would anyone do that? Why can't reporters answer basic questions like, 'why are these guys getting suspended'?