vibration on acceleration

I have an 08 Outback, automatic. I am experiencing an occasional light vibration upon light acceleration at lower rpms 1500-2000 and after shifting in the lower gears. It doesn't seem to come from anywhere in particular. I brought the vehicle to a local dealer who did a multipoint vehicle inspection and said everything looked solid and couldn't find any issues. I am wondering if anyone else has experienced this or thinks there could be something wrong that could be an issue. Thanks.