Our LS 400 infrequently and absolutely randomly will stall while deaccelating from highway speed when entering an off ramp. This is the only circumstance under which the problem has ever occurred. The throttle body was initially cleaned and later replaced by our Lexus dealer and this seemed to help, but 60,000 miles later the problem has returned. Upon stalling the engine immediately restarts and we may go months without a recurrence. The throttle body was replaced at about 160,000 miles and the car is now at 220,000.

Thanks for any help you can offer.

 

You don't say which year LS you have as there was a problem with the engine ECU on some 3rd generation models causing this although many were sorted under warranty.
Other causes could be the TB again needs cleaning,the IACV needs cleaning or you have a vacuum leak somewhere.
Also it could be a low fuel pressure problem,easily checked.When was the fuel filter last replaced?

 

Sorry about the missing information on my first ever posting. We have a 1995 LS 400. Typically, I replace the fuel filter yearly and my mechanic says the 60,000 old TB looks brand new when he took it apart.

fawski

 

Wait - This happened to my sister's 1996 LS400 this December 2010. The problem was the torque converter. Quick question: does it slightly sputter to a halt or does the engine gradually and smoothly just die?