The "throttle body" is called the throttle actuator, and it is a part that goes bad. I had to replace mine.
It's an expensive gamble, though, as the part is a little over $1,000.
Also, faulty cruise control is a sign that your actuator is going bad.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".