I just got the Makita LXT 18v impact driver (BTD141). I was under the impression it would be faster than my current compact drill/driver (makita 18v Ni-MH) but it seems to putter out when there is any amount of resistance. It works fine of course, but the last inch or so is pretty slow. This is while driving a standard 1.75 inch deck screw into a 4x4. Is this normal - is there anything I can do to make it faster? If this were my drill/driver I would either put it on drill mode or increase the torque setting. Is there anything equivalent for the impact driver?