One problem related to gas recirculation valve (egr valve) has been reported for the 1998 Chevrolet Blazer. The most recently reported issues are listed below.
There was a class action regarding the dexcool coolant issues that degraded the engine gaskets. I had not known of it as the manufacture or other did not notify of it. The only way I found out was searching for another car issue online a few years after the said issue. What is this, 'keep all a secret so we do not have to deal with it. '? this has been a few years ago, hence the Jan 2010 date entry as guess to the date of online knowledge. If a closer date needed; I can research.