I use OD to rev till rpm btween 4-5k and hold for 10 mins to clear carbon. Do this abt once/mth. Speed will be from 110-130km/hr with OD. 
Hi
I am just think aloud. I was advised by my friend to pump V-power to clean the engine.
Any guys or gals knows whether TCM's regular servicing (1K, 5K, 10K, etc) include purging the carbon from the exhaust?
Rgds