Hi there!  happy to have stumbled upon your site.  I bought a used 35K mile 2009 Lexus is250.  Did have in it's past I find....a 2015 a service by Lexus ZLA campaign to clean carbon from cylinders/valves and replace pistons/rings. So looking into the future, now at 69,000 miles I have serviced the car but took into dealer for tune up/spark plugs and dealer recommends throttle body clean for carbon build up. No scoped was used. I have only had one time that the car shook at a red light, 2 mos ago....but never died on me. With this direct injection engine model, would you recommend that I cut my losses and say goodbye/sell it...... or simply do yearly throttle clean and hope for the best?  Thankyou! Kim in texas