Well I had some trouble with the car staling on the first start and I took it in last month to get it checked out and there is a ECU upgrade out there if any one else has this going on. TSBI EG007-06 I hope this helps out.

 

I think this is only for the IS 250. Here's what I found about this:

3/31/2006 - 2006 model year Lexus IS250 vehicles equipped with the 4GR–FSE engine produced BEFORE the Production Change Effective VINs shown.

Under certain driving conditions, some 2006 model year IS 250 vehicles may exhibit a M.I.L. “ON” condition with one or both of the following DTCs:
􀀀 P0172 (System Too Rich [Bank 1])
􀀀 P0175 (System Too Rich [Bank 2])
The Engine Control Module (ECM) (SAE term: Powertrain Control Module/PCM) logic has been modified to improve this condition.

NOTE:
􀀀 Version 13.3a or later Diagnostic Tester software is required to perform
this procedure.
􀀀 Before proceeding, verify the ECM (PCM) calibration has NOT been updated
by checking for the Authorized Modifications Label (shown in step 1 of the
Repair Procedure).

 

Thanks for the great info.

 

Does anyone know if this update would have been added to a new car if it was purchased after the TSB was issued. I bought my car mid April, and it is one of th ones before the production change. Do dealers update cars with TSBs before they are let go from the lot?

 

You can find all the latest Toyota/Lexus Technical Service Info Bulletins here aka "TSIB" for a nominal fee. Commonly known as "TSB".

http://techinfo.toyota.com