hi therejust reading ur probs we have experiance on lexuses 400/430,s etc when u say ur emissions are high is it c/o or lamba ? we are currently breaking 400 ls long w/base 94 model but i would suggest check air filter[dirty]make sure the vehicle is upto normall operating temperature,allso a slight leak on your exhaust can give you all the syptoms ur havin hope you get it fixed phil e