Hi guys - new owner here; bought my LS400 yesterday. I'm loving it, but just encountered a disapointing problem. It drives beautifully, and pulls really well too, but i tried kickdown and when the revs hit around 5k it stuttered and bounced and wouldn't go past it. It said check engine on the dash, but as soon as i stopped accelerating the message dissapeared. I tried acceleraring more gently without kickdown, and sure enough, the same thing happens at around 5k.
The car has 118k on it, is in lovely condition and has recently had a cambelt, waterpump and service.