One problem related to gas recirculation valve (egr valve) has been reported for the 2006 Nissan Sentra. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Nissan Sentra based on all problems reported for the 2006 Sentra.
On 2006 Nissan Sentra se-r spec v, I noticed a drop in power and excessive oil consumption. Upon pulling the header I noticed pieces of the catalyst broken up in the exhaust pipe. The egr system may have sucked in pieces of debris damaging the cylinder walls.