...in any way? The EGR valve in my 98 Honda Accord has been malfunctioning for ~6 months. If I am not required to pass the emmision tests (which will automatically fail if the check engine light is on), then do I have to repair the valve (costs $250). Does the malfunctioning EGR valve have any impact on the long term engine performance in 98 Honda Accord?

yes if in fact you are haveing problems with it it will flood out your engine causing gas to drain but not to flow through to the lines but leak out somewhere