had low power and missing on acceleration: have replaced:
timing belt, idler brg,tensioner,
plugs
leads
distributor rotors
caps
w.pump
accesory drive belt and pulleys,
still chasing low power on acceleration after about 3-4000rpm.
full throttle gives acceleration to 3-4000rpm, then it labours and wont go over 5000 till u bak off and then it changes up and accelerates till the same again occurs.
On scanning, no codes appear.
any ideas guys???/

Hi and Welcome to the LOC.

Maybe have a look at the fuel filter sounds like its not getting enough fuel,also check the air filter.

changed fuel filter and air filter is ok.
also put two new cats on.

Maybe try posting this topic on the US forum they might be able to help you,sorry dont know what else it could be.

http://us.lexusownersclub.com/forums/

Let us know if you find a fix.

Cheers chips.

throttle position sensor or dirty throttle body or
, poss ECU probs.