2010 175 hp regular optimax 1B789623. This thing idles rough and stalls when started , but lines out and idles fine after it's warmed up. It runs great at every speed above idle, but runs rough at idle when in gear, especially when putting the boat on the trailer. Over the years, I've installed fiber reeds, multiple plug sets, new air compressor, new tps, changed fuel lines, replaced low pressure fuel pump diaphrams, checked fuel/air pressures, compression, leak down rate, but this engine still has never run well when cold at idle or idling in gear. Is this just the nature of the 2.5? What else could it be?