Cleaning up the sketch...due to display value bounce

I am having an issue with this project, overall it is working well, but at some points the value starts to deviate up and down at the refresh rate, and at times the deviation is very large like 50 degrees, sometimes it is only a few degrees and most of the time it is rock steady, and dead nuts accurate.

I am wanting to eliminate anything in the sketch that is not absolutely necessary for it to work and compile. So I am wanting suggestions from you guys and I will try them. When I try to eliminate things I get into compile issues.

I think every line in the loop function is necessary , but the other parts may have similar but interfering lines or completely unnecessary lines. I am wanting to condense it and clean it up to have minimum complexity. I kept adding things and modifying things until I got it to work, but having trouble taking things back out and getting it to compile.

Any help will be appreciated
Best regards Skip

PorSCHE_3.1F.ino (8.21 KB)