Dsmale

I have just bought a 2008 Subaru Legacy 2.5i limited. I have changed spark plugs and wires, oil change with filter, air filter, took the throttle off and cleaned. When I am in park I can give it gas and the rpms will rev. I place it in drive and it’s a slow start to move and the ramps will go to almost 4 and I can’t go over 20mph. Also at times almost bucks. I don’t know what else to do