You do know the diesel is an automated manual transmission and needs time to push in the clutch, change gears and let the clutch out? The first to second shift is slow, the rest seem good. The gas vans on here are getting about 17 mpg combined city/highway and the diesels are getting about 26 combined. Most of us are very happy with that. Heavily loaded, pulling a trailer we are seeing 21+ for the diesel. You idling a lot? DON’T- the diesel warns against it and the gas drivers who have idled a lot have seen a couple engine failures. The days of idling are over.