What is causing engine vibration/lugging?
The engine/auto trans combination perform as expected in all speed ranges and gears except for speeds between about 50-60mph in D. It gets worse when going up a shallow hill. In this speed range the engine is turning over at 1400-2000 rpm. The vibration can be relieved somewhat by moving into 3 rd gear. It is sensed through the throttel pedal as well as by sound. I have run it with premium gas and put the KD44 thrugh the gas system but with no change. Problem may be worse in heat ald less in cooler environment, but not by much. The dealer's mechanic said that the vehicle is running as designed, but I can't believe that Toyota would put something like this on the road.
Is this normal?
Can this be repaired?
TIA