Well the car isn't mine. When you got 5 vehicles to take car, boats and other equipment to take care of......... 2 times a year is excessive to clean the TB, unless you put on 70k miles a year. EGR also dirtys up the TB at a faster rate.

The OP has over 90k miles on his and the TB probably wasn't ever cleaned. To do it right he has to pull the TB off for cleaning.