Car doesn't move when I first start driving

I drive a 2002 Lexus ls430 with 136k miles, 1 previous owner.. Recently when I first start my car and put It into drive, it will feel as though it's in neutral. I can hear the engine revving but it will barely Roll along until I push further on the pedal. It will violently jerk and then it's back to as if it never happened for the rest of the day. Same when I reverse. I was told by a mechanic that I need a tuneup, spark plugs, everything that comes with it. Is that really what's causing my car to act like this?