Two problems related to engine exhaust system have been reported for the 1999 Chevrolet Silverado 1500. The most recently reported issues are listed below.
Exhaust manifold bolts breaking off.
1999-20?? gm 5. 3 liter engine. Left side exhaust manifold, last bolt back head has popped off. I have seen four other motors like this and have heard of several more. This allows exhaust gases to enter the cabin area posing a risk of CO poisoning.