how do we get this from sticking. it usually only does this when we change elevation.
EGR Vaulve Sticking open on 1994 Chevrolet S10 Blazer
The problem may be with the EGR valve or carbon build-up in the engine. Carbon bits can work their way loose when the engine is under heavy load - climbing hills. The carbon can stick in the EGR valve holding it open. The valve may or may not clear itself out. Performing a "top engine decarbonization" procedure may help or correct this condition. Any good repair shop should be able to perform this procedure, It may be a bit complicated if you have never done it before. If the engine decarbonization does not correct the problem you may need to replace the EGR valve.