How do you know if your egr valve or sensor is bad on your 1993 Toyota t-100?

To determine if the EGR valve or sensor on your 1993 Toyota T-100 is faulty, look for symptoms like rough idling, decreased engine performance, or increased emissions. You can also perform a visual inspection for carbon buildup or leaks around the EGR valve. Testing the sensor with a multimeter for proper voltage readings when the engine is running can help confirm its condition. Additionally, an error code related to the EGR system from an OBD-I scanner can indicate a malfunction.