I have noticed that when I am pulling my trailer at a slow speed, and I have to take off, the engine will knock very slightly right at the downshift. This has only recently started; I have 3,800 miles. Is this something to be worried about? My old truck did this when I used cheap gas, but now I only use Chevron 87 octane. Should I up the octane?

 

I would try a tank of higher octane, and might even switch gas stations for a starter. Then mention it to your dealers service dept as well.