What does EGR mean?
 

Just what the subject says, and what does it do?

Exhaust Gas Recirculaton => its a circuit that bleeds small amounts of exhaust gas from the exhaust ports/manifold and directs it back into the air intake stream. The purpose of doing so is to lower emmissions (NOx particularly) at low & part throttle conditions. The EGR circuit is closed a high load and WOT conditions.

Oh, ok. Thanks alot