When I start my 7.3 in the morning when temperatures are around 5 degrees Fahrenheit or lower, I’ll let the glow plugs heat up for at least 2 minutes (truck unplugged) and when the truck starts, immediately the rpms will be at 1500 with a rough idle and will slowly drop to about 1200. Unless this is normal, I can’t imagine this is good for the engine. Any thoughts? The truck does not do this when temperatures are slightly warmer. Thanks everyone!