Intermittent sluggish acceleration avensis 2ww

[Briano]

Hi All,

Looking for some advice, on occasion the car is very slow to accelerate in all gears when down low in the revs (1000 - 1500 rpm) - have to press the accelerator fully or drop down a gear to get it moving. Once over that rev range it is perfectly normal. Stop the car and restart and the problem is gone - will accelerate from low revs only half pressing the accelerator.  Any ideas? Car has 186000km on the clock and is fully serviced to date. 

Thanks

Brian