need regular "tune up" because the computer in the
car keeps the engine running in perfect condition
from automatically adjusting the air-fuel ratio to firing the spark
plugs
Never. Cars do not need "tune-ups" since the advent of electronic ignitions (1975-ish) and common standard usage of platinum (or iridium) spark plugs (late 1990s).
Of course, however, every gasoline vehicle obviously still needs periodic replacement of its spark plugs, filters, and other parts. This is now called "periodic maintenance", "regular service", etc.
Newer cars only every 100,000 miles.
Every 100k miles
When needed.
