The EGR valve controls a passageway between the intake and exhaust manifolds. When the valve opens, the intake vacuum draws exhaust through the valve. This dilutes the incoming air/fuel mixture and has a quenching effect on combustion temperatures. Remember to always replace your faulty EGR valve with the model that corresponds to your year/model’s engine.
Direct replacement for GM part numbers:
For 5.7L 350 ci V8 with manual transmission.