Dear Scotty,

really love the way you are not only busting car myths, but are also explaining what is or was behind them.
So below a short list of some more car-related theories you might want to dwell on:

1) Under certain circumstances small pieces of a catalytic converter might get sucked into the engines, thus destroying cylinders from the inside.

2) In a jacked up tire, the tire pressure is lower than when the car is standing on the ground, cause in the latter case the weight of the car itself adds up to the atmospheric pressure which compresses the tire from the outside.

3) If you want even tire wear, especially for low-profile tires, pressure in your forward tires shall be higher than in your rear ones, to compensate for the fact that due to the actual steering the outer edges of your front tires are contacting the ground (thus wearing out) way more intensively that the outer edges of the rear tires which cannot steer.

4) In cars with batteries located not under the hood (but in trunks or under rear seats etc.), the voltage regulators (which are located on the alternator, and which have a temperature compensation function which limits battery charging voltage depending on the temperature, which they measure not on the battery but inside the voltage regulator body) do a bad job and tend to be charging the battery with a too low voltage, because the temperature on the alternator, sitting next to the hot motor, is much higher than that in the, say, air-conditioned passenger compartment of a car. Hence, in cars with batteries located not under the hood batteries tend to be chronically undercharged.

5) If roads in your area tend to have significant grooves (wheel ruts) in them, you should over-inflate your tires (run your vehicle with a tire pressure which is higher than the factory specs) to compensate for the fact, that otherwise those ruts would cause premature wear of your tires` outer edges. 

6) If roads in your area are bad quality, you should (especially when using low-profile tires) also over-inflate your tires to make your wheels more resilient against potholes, cause uneven tire wear caused by over-inflation is a much lesser evil than having to replace expensive alloy wheels after each pothole.

7) Spark plugs, if undamaged, as well as if cleaned (e.g. cooked in Coca-Cola 🙂  )and gapped correctly, can be used a virtually unlimited number of times - no need to throw them away and replace with new ones until they show some tangible defects.

Hope you at least had some fun reading all of these 😉

Best Regards.