One problem related to gas recirculation valve (egr valve) has been reported for the 2002 GMC Sierra. The most recently reported issues are listed below.
The oil light illuminated after 2500 miles. The consumer found out that the vehicle had consumed over 2 quarts of oil and emitted blue smoke when started cold. The dealer replaced the pcv valve as a cause but the vehicle continued smoking and consuming more oil, the dealer informed the consumer that eventually they would have a redesigned valve cover to prevent the problem, but that they could do no more at this time.