Pics of what Frank said:
http://www.flickr.com/photos/14751890@N03/7027156235/in/photostream
http://www.flickr.com/photos/14751890@N03/7027156319/in/photostream
Same thing happened to my 93 K11. Did the throttle body diy fix but turned out to be the Distributor breaking down. Got one from scrappy and problem was gone.