This will sound stupid, but worth telling everyone.
A relative's car had been making a ticking noise--similar to valves starving for oil as in low oil pressure, or timing chain. This had been going on for 1/2 year. Yesterday, the real reason finally showed up. One spark plug was loose and finally pulled away from the threaded socket. Of ccourse, a loud noise came out. Now with the spark plug tighten up, that noise is gone and car runs fine.
Just thought about passing that info. It sound stupid but it could happen to anyone who has a ticking noise in the engine.