Hello Mr. Kilmer.  I have a 2009 Lexus ES350 with 155000 miles on it. The vehicle is in pretty good condition. But I do have one issue. Sometimes, under heavy acceleration, especially on the highway, the VSC light may be triggered.  When this happens, the vehicle loses about  1/3 of its acceleration power.    

I tried to self diagnose the vehicle and noticed that whenever the sensor for the air filter is unplugged, the VSC light will appear in the dashboard.  I presumed that the appearance of the VSC light has something to do with the air filter so I changed it. 

I took the vehicle on another test on the road and the VSC light reappeared again under heavy acceleration.  I even took the vehicle to a Lexus dealership and they told me that there's a possibility that they could be carbon buildup somewhere between the engine and the muffler. 

My next step was to pour inside of the fuel tank certain fuel additives and fuel cleaners in an attempt to remove whatever build up that might be in the catalytic converter system and or engine. 

Do you suggest that I should continue to add fuel additives to this vehicle and hopes that it will knock out whatever carbon is in the system? Or should I give up and say that this car can never be used under heavy acceleration again?  After all, I like to haul ass on the highway. So having this as a fast car is important to me.