I'm new to the forum. I have a 2018 EcoDiesel that's now in the shop for a new intake manifold.... When I took it in, they asked me when was the last time I had it on the highway. It was probably 1-2 months ago. They told me that if it isn't driven hard (60-65mph at high rpm) at least once a month, emission particulate build up and cause damage... I don't have occasion to drive on the highway often. So this may not work for the type of driving I do. Is their advice correct? If so, I may trade it in on a Cummins 2500....if that doesn't have the same problem.