Tune up using Timing Light

[1D4LV]

aside from regualar change oil, change spark plugs.. etc..
what struck me most is that when the mechanic used a timing light..
uhmm..
Is it really effective?
Does it really tunes your car engine?

thanx

parang...kasi speaking from experience, pag di ako nagpapaganito parang may vibration yung oto ko from the engine bay while running eh. compared to, if ginawa ito, medyo nag hu-humm lang ang tunog ng makita.

pero dunno how the process works though...