Q: egr valve

The first EGR system was installed on cars starting in the early 70’s. The engines before this did not have one and the emissions of NOX was high. The EGR system helped to reduce the output of NOX and allowed the ignition timing to be increased. Your engine if equipped with an EGR valve can run without the valve but may cause the engine to have pre-ignition pinging that could lead to holes burned in the pistons or spark plugs getting melted. You would need to lower the ignition timing until no pre-ignition is happening. The lower ignition timing will cause loss of some power, higher fuel consumption, lower idle, hesitations and surges. Also modification of emission components or removal is illegal,