I changed out my Speedo gear too. This is the part I was referring to.I'll report back once I install the new CPS sensor and test drive. Yes, I had to regear due to having 33s. I probably drove 6 mos with 33s and 3.07 gears before regearing with no issues, but I probably never got over 3k rpm. I also added the correct speedo gears if that's what you are referring to by speed sensor.
https://www.quadratec.com/products/55200_0101.htm
I have no idea what it does but wondering if it can cause misfiring?