hershey wrote:
I don't think it will have any effect on your emission test.  Suggest you run the RV fairly hard just before the test and arrive with it at full operating temperature.  Never test a cold engine.
X2 on this.  SeaFoam is great stuff for keeping engine fuel systems clean but don't over use it is my recommendation.  My diesel vehicles gets a treated tank full every year which directly after running that tank through I change the fuel filters to make sure nothing gets into the engines.  That stuff cleans good so don't over use it or use it on a vehicle that has an excessively dirty fuel system unless prepared to deal with the junk it loosens up.