Hi:
very nice project, I love this kind of thing, when adults and kids both learn a lot.

I'm pretty sure that the problem with fast cars are all those serial and LCD prints in the if's.
try once you detect the first sensor trig, do nothing until you detect the second (put a timeout just in case) the do all the math...

Hi Rudy:
in my project, nothing similar to your description occurs.
It is possible that your problem is related with some particularity of the NodeMCU, I really don't know. sorry

thanks for your words, but certainly it's is far away of my possibilities and expertise. Beside that, manufacturing and exporting electronic device from this part of the world (Argentina, South America) is economically inconvenient.
You could buy a better one in openenergymonitor.org