So the wife has an 06 Yukon (5.3l) 167K. OK so I'm not sure where to start looking, Yesterday on her way home with the kids she started getting a slight miss fire. This morning when she left for work and take the kids to school the miss fire got worse to the point she turned around and want back home. Once in the garage she noticed oil leaking from the passenger side front of the truck. Would this be in intake gasket or something else? Any ideas and any help would be great?