Lexus Repair: She shakes, denso plugs, torque converter

Question
I brought a used LS400 91 Lexus from an auction. I don't know of any repairs done. Only that she passed smog. Now she shakes while I'm in drive on the brake. Do you think I need a full tune-up or do you think that I can just get the spark plugs replaced.  

Answer
It depends on what's shaking. Normally you would replace the brake pads, rotors & flush the brake fluid if it's the brake system.
(Yes) Give the engine it's ENTIRE routine tune-up maintenance. Including inspecting all enigne, transmission, and suspension mounts.
Toyota didn't spend atleast a billion dollars to develope that engine to go half way on maintenance!

Don't go half-way just putting plugs in (Which MUST be NGK, or Denso plugs. NGK, or Denso spark plug wires. Change the distributor caps & rotors. Check that the fuel system is up to par.)


Check the transmission fluid & that the torque converter lock-up is disengaged when it should be.