Fuel return lines at injectors. Go bad all the time. Cigar hose on return line common. Some folks have had trouble with lines leaking at the tank. At least one person reported fuel lines had rusted thru under the body (Yikes!). I don't mind the smell of diesel, but wife HATES it. We now have two diesel cars and I hope to get two more. I'll let her keep her gas V8 as long as I get to drive it when I feel the need. (yeah, like I could take it away....and live)