Changed my oil today and noticed it was very dark in color. Oil has always been changed at 5k miles with full synthetic and I have never seen it that dark in 58k miles. The only thing I can think of is maybe cheap oil? Last oil change the dealership did it and used Motorcraft full synthetic, I don't think I'll be using that again. This time I went with Castrol Edge full synth, so hopefully that will improve with the next oil change. I didn't see any metal flakes in it or anything, I was just very surprised to see how dark it was, and with the way these cars tend to build up sludge I just want to make sure I'm taking all the precautions I can, especially since I'm just about out of my powertrain warranty.