Regular highway driving usually helps to prevent carbon from accumulating on the EGR valve. A good quality fuel and regular use of fuel injection cleaner should help, too. I wouldn t recommend switching to a premium grade of fuel, though. The lower octane level fuels have additives, too. Yes, the EGR valve can be cleaned and doesn t always have to be replaced. But make sure to take an occasional drive on the highway. Also, it should help to use a fuel injection cleaner maybe once a month.