The EGR valve is mostly located on the intake manifold. In most cases, a problem that occurs within the exhaust emission system is because of a stuck or faulty EGR valve. To prevent burns, press on the EGR valve diaphragm while the engine is cold. Pushing the diaphragm up into the housing should take some force but not too much. Removal of air filter housing may be necessary to access four-cylinder engines' EGR valves. If in doubt replace it with a new one. However, comparing free movement between your EGR and a new one could tell you how bad it is.