There is a funny scene in the movie Ford vs. Ferrari where then-auto mechanic Ken Miles (Christian Bale) tells a customer that there’s nothing wrong with his sports car—except that the driver won’t drive it in the manner it was built to be driven. The customer safely drives it in low gears and never takes it to the highway or rural routes where he can shift it into high gear and see what it can do.
Old British cars need to be revved. An old de-carbonising method was to get out on the road and get up to about 50 mph and drop back into 2nd gear, spinning up the revs and blowing out the cobwebs.
Ken Miles was just telling the guy to shift at higher rpms so the engine wouldn’t load up.
Re:
no shifting
In the service we had to be trained on driving 2 1/2 ton truck for our MOS.
We had one guy that had some sort of dyslexia or similar. Would not shift the truck.
Left it on one gear and that was it. Drove us up the wall he would not shift.