Welcome to the first Saturday Q&A of August! This week, Nile (Motormouth) Jenkins answers three excellent questions from listeners Julie, Wendy, Allison.

Julie asks whether the large plastic panel under her vehicle is really "not needed" after it was damaged while backing out of a parking space. Learn why that component plays an important role in engine cooling and aerodynamics.

Wendy wants to know if tune-ups are still necessary on today's vehicles. The answer may surprise you. Modern engines have changed, but preventative maintenance hasn't disappeared. Find out what a proper tune-up looks like today and why waiting until something fails can become an expensive mistake.

Finally, Allison asks if fuel system service is legitimate or just another upsell. Nile explains the difference between a professional fuel injection decar ...