wow, "有力氣但是沒勁'? have you ever had an mb diesel car/truck?
most diesel engines have the peak torque at 1600-1700 rpm. why would you expect it gets more than 2000 or 3000 rpm?
in california, gas is about 2.89 or up, while diesel is about 2.63. a few days ago when i passed lost hills, i filled up at 2.39.