EGR = exhaust gas recirculation. A small amount of exhaust gas is metered into the intake charge to reduce peak combustion temperatures. This allows higher compression ratios without detonation (“ping”) and reduces oxides of nitrogen emissions.
To locate the EGR metering valve, follow the intake air duct from the air cleaner to the intake plenum (it has a metal plate on top with an embossed running horse). The valve is the black “top hat” mounted on the opposite end of the plenum. It has a vacuum hose fitting on top.
Directly behind the EGR valve, near the firewall, is a bracket with the EGR actuator (front side) and EGR differential pressure sensor (rear side) mounted on it. The pressure sensor measures the amount of exhaust gas flow and sends that information to the power train computer.