Why when i accelarate it struggles then starts to acelarate not every it often jerks

What is your question?

When I mash gas it cuts back struggling to accelerate but rpms go up before start accelerate I have changed plugs thinking it might be misfired changed the valve cover gasket think maybe 02 sensor took to shadetree guy he said transmission looking for a possible answer to my problem please help even a leak in air intake cattalic converter ........ ...............................................................................................................................

What makes this problem better or worse?

I don't know but it don't happen every time I acel

How long has your 2000 Lexus RX300 had this problem?

8 months