The EGR (exhaust gas recirculation) system directs some non-combustible
exhaust gas into the cylinders to reduce the combustion chamber temperature
with the intention of reducing Nitogen Oxide formation (a smog component).
There is a performance cost to recirculating exhaust into the combustion
chamber. I probably need it here in Sacramento (tenth worst air in the
nation) but I doubt that you need it in Canada. That is between you and the
government that regulates you.

Steve
81 Vanagon Myrtle the Turtle