Intake Manifold water leaks

[Oliver77]

My 2000 Silverado 4.3 is starting to have a problem similar to a 97 Olds 88 we used to have. The throttle sticks in the closed position and it takes a hard punch to loosen it. When this happened on the Olds we found that the upper intake plenum had a coolant leak and the lower plenum was full of a coolant. This apparently was a common problem on the 3.8 V-6's, and GM made a change to the intakes to eliminate the it. Does any problem like this exist with the 4.3?

[99ssconv]

you need to clean the throttle body plate with carb cleaner, when was the last time it was done? recommend at least every 30,000 miles.