Two problems related to engine exhaust system have been reported for the 1997 GMC Sierra. The most recently reported issues are listed below.
Exhaust flange gasket failed. Nlm.
Loose body bolts;repaired by dealer. Had evo sensor replaced at a chevy dealer since they knew about the problem that affected this new feature, electronic variable orifice was new in 1997. The truck was dangarous to drive, felt like a go-cart, all over the place. They chevy dealer also burned in a new program for mixtures and timing went they replaced both O2 sensors and cleaned the egr valve. Did I pay to replace these items due to a bad program?? I think I did. What is warrenty on emission system from the manufacturer. ???.