Hi Dave,
Does the engine have issues at intermittent spots, or does the problem occur in the same general area? Have you tried running it the opposite direction? I have several ETS engines and have used them on various track systems. A couple are finicky runners and these need the track to be very clean. I had issues with the VW cars and traction tires fixed the problem. I have had issues with imperfections in a couple of fastrack pieces. My 249e would just stop and spin the wheels. Every other engine ran fine through that section,
Did you order directly from ETS? If so, how was the shipping cost?