here's some of the tsb
GR–FSE SERIES ENGINE OIL LEAK – EG001-07 February 16, 2007
Page 3 of 4
1. Remove the engine assembly.
Refer to the Technical Information System (TIS), 2006 model year GS 300, IS 250, or
IS 350 Repair Manual, Engine/Hybrid System – Engine Mechanical –
“3GR/4GR/2GR–FSE (applicable engine) Engine Mechanical: Engine Assembly:
Removal”.
2. Disassemble the engine to remove the timing cover and replace the RH and LH
Camshaft Housing Sub–assemblies.
Refer to TIS, 2006 model year GS 300, IS 250, or IS 350 Repair Manual,
Engine/Hybrid System – Engine Mechanical – “3GR/4GR/2GR–FSE (applicable
engine) Engine Mechanical: Engine Unit: Disassembly” (steps 1–57 only).
3. Reassemble the engine.
Refer to TIS, 2006 model year GS 300, IS 250, or IS 350 Repair Manual,
Engine/Hybrid System – Engine Mechanical – “3GR/4GR/2GR–FSE (applicable
engine) Engine Mechanical: Engine Unit: Reassembly” (steps 30–75 only).

 

If you're your own oil change, make sure to check for tramisssion leak and loosing bolt. My car and some other car has loosing bolts and very very minimal leak. Toque it abut and you good to go. My cousin works for Lexus of Westminster also confirmed me that lot of 2IS has that problem.

 

and heres a whole thread about it
https://www.clublexus.com/forums/is-...-leak-tsb.html

 

So if anyone here has done the TSB, what was the symptoms? Mine gives me a slight whiff of burnt oil every once in a while but there is no leak on the ground. It has burned some oil over 2500 miles (from upper to lower mark on oilstick).