I had a guy try to do a tune up on 03 gs 300 wich turned into a nightmare for me any way since ive loss all my power ive replaced coils wires throttle sensor new valve cover gaskets nothins worked i was wonderin if new spark plug tubes would help with loss power im runnin outta ideas but im not a mechanic and cant pay dealer or shop prices

 

There isn't anything that would be considered spark plug tubes on the 2jz. Do you know which cylinders are misfiring?