Some of the symptoms of a bad EGR valve or a Exhaust Gas Recirculation valve are inefficient combustion, rough idling, hesitation, and sometimes stalling if it is an extreme case.
The symptoms of a bad EGR valve are hard starting, rough idling, cruise control surges, popping noises from the exhaust, and sudden engine stops in cold weather or after deceleration.
The symptoms of a bad EGR valve are quite easy to spot when you know what to look for when running the car does black smoke billow form the exhaust as opposed to grey this is the main test.
Symptoms of a bad EGR valve are basically that the car will run unevenly while the engine is idling and high fuel consumption. The cause of this is usually a stuck valve.
If you have this problem with your valve you could experience different issues such as gas mileage. You may lose up to 2 miles per gallon if you let this problem continue.
