The problem might lie with where you got the car from. I've read around about the Lexus ls400 because I want one and everywhere I've heard that you should avoid an import from Singapore, no matter how expensive, cheap, or otherwise. 99% of the cars from there are given a 'death sentence from the factory' if you will. Just thought I'd let you know...
LS 400 Forged cross drilled crank, six bolt mains, rated at 250 HP, bottom end untouched is good for 850 HP.
Ancillaries are manufactured by third parties, not Lexus.
I didn't read this thread before buying a Singaporean import 1999 LS400. Mine to was a bit of a lemon at first, but have sorted most of its trouble out now. Did the cam belt as it was due age wise, not mileage wise, and it was shot to hell. The heat in Singapore really affects the under hood temperatures and the plastics tend to get very brittle. The cam position sensor clip was broken by the mechanic who changed the belt (probably the same as yours) and therefore I also had a bucking bronco. Nasty experience, but you would have thought a Toyota service centre would take more care. Finally took it to Lexus and the diagnosed it with the OBD2 computer.
Also had an extremely rare instrument cluster fault, never found a secondhand unit, but imported one from the UK.
Air-con condenser also had to be replaced as the old one had corroded in the salty Singaporean air.
Still, the car is a dream on the open road, reasonable MPG when driven gently and still my favourite series of them all. Will wait patiently for a NZ new one with all the options before I buy another one.
Well I just did research on the Lexus LS400 from all years and the only place I can find it being manufactured is the Tahara factory in Japan consistently since 1989. The Tahara plant remains the sole production site. I do not know where this Singapore stuff is coming from but it is false information.
FYI the Singapore cars people are referring to are of course not manufactured in Singapore, and are indeed made in Japan. These cars are originally imported into Singapore, and unfortunately the extreme humidity and salty air as someone mentioned, play havoc with the cars electronics, wiring, seals, etc. Don't touch them.
I have owned my second hand 1998 Lexus LS400 for three years now, and the only fault it has, is the door lock switch on the front passenger door is broken. The car was imported from Singapore a number of years ago, and I am the second owner in New Zealand. It has travelled 164000 kms and runs like a dream. It has the VVT (Variable Valve) engine, and when asked, stands on its hind legs and fair tromps. Took it to 180 kmph, and it was still pulling away. As steady as a rock. I stopped accelerating at that point, visualizing a cow wandering onto the road in front of me.
It is without doubt the most smooth and quiet running vehicle I have ever driven. It is meek and mild when driven quietly, performs when asked, and is relatively economic as well. I used to drive V6 Holdens, and this uses no more fuel than they did. For a small V8, I think that is marvelous. I would love to upgrade to a 430, but I don't want to part with this one.
Anyone who has problems with one of these, I think must be a rare bird, because I have heard nothing but great reports about them, and my experience just re enforces that. I have heard say they have been rated as the most reliable car ever.
Stu in Cambridge, New Zealand.