I have a 740 turbo, auto transmission. Recently I took it in to have poor mileage checked, and the smell of gasoline was present (inside) whenever I started the car, and outside the car almost all the time. The mechanic said that the wastegate was stuck open and he oiled it as best he could. He also replaced a worn hose and clamp. I filled up again, and checked my mileage. Where it was 13 mpg (all city) before the mechanic trip, it was now 10 mpg for the same city trips. We had a couple of cold days where it warmed up longer than usual, but I don't know if that would make that big a difference. I feel bad that my little Volvo is not getting any better mileage than a Hummer! Does anyone know what could be causing such crappy mileage. I do not have a lead foot, do not let the car idle, and it seems to run fine, not rough. I would love to be able to fix this rather than think about a whole new turbocharger like the mechanic said would be necessary if the wastegate gets stuck open again. Thanks for any info.