EGR is a good thing for all vehicles driven on the street.. Exhaust Gas Recirculation. Its purpose is to vent exhaust gasses into your intake manifold to reduce emissions and more importantly reduce the chance of detonation on slight/moderate acceleration. Many people think that this will impare performance.. They are mistaken, it actually improves performance by eliminating the above problems..Now on full accel,, this could cause a performance decrease, this is why the OEM's program into the Fuel injection Map, to eliminate EGR activation.. Concerning your problem,, you can have a EGR lift problem or an EGR Flow problem.. EGR Lift code will tellyou that either the Valve itself is sticking or the vacuum/electrical signal is missing, depending your engine. EGR Flow code means that the ports them selves are clogged and need cleaning..Hope this helps..