One problem related to catalytic convertor has been reported for the 1999 Chevrolet Silverado. The most recently reported issues are listed below.
I took my truck to the dealership mentioned above. When they hooked the computer up to my truck it showed 2 problems. One is that the egr valve is bad and the other being the catalyticd converter. They are going to charge me $275 + tax. That is with 1 1/2 labor.