Just to clarify ---there is a bit ,not much-- i do let it idle between some calls(i'm delivering pita bread/bagels/wraps etc)NO PIANOS,but believe me,bread can get heavy. I load this 16ft cube F450 to the nuts everyday,just enough room for me to squeeze down a 18 inch middle after loaded(22 stacks-13 trays high,30-40 stops/12hour day). In the summer with a/c on,but no idle time the best i can get with approx 85% city15% highway driving is 10-12 MPG,all of the last 8 Ford F450 we have run are identical,(same motor/transmission/size,97-01)and the mileage is the same with all. This truck has only been driven by me(225,000 current miles),no internal motor work done---yet,original turbo/glowplugs/injectors,but it feels like its getting tired. Another Bread driver has the same running gear in F450 pickup and best he gets empty is 14-16MPG:{:{:{. As i have said in other post before---THERE IS A REASON WHY I HAVE A CUMMINS IN MY GARAGE WHEN REAL WORK IS NEEDED. -----PS my only gripe with the Cummins is maybe Dodge could of learned/stole Fords design for a fuel pump/lift pump---with all our company Ford we have never(yet) had a fuel pump failure-go figure---My 2 cents---Sorry for the long post guys/gals. DW