Pendejo is a vulgar Spanish-language term of abuse. To call a person a pendejo is essentially to call him stupid, although it also carries implications of wilful stubbornness and rank ineptitude.
A toilet may run periodically due to a problem with the flapper, the flapper seal, the flapper chain or a high float.
A constantly running toilet is testing your sanity. THE QUICK FIX. The problem is most likely the flapper valve not sealing properly. First, make sure that nothing--such as a brick to raise the water level or a toilet-bowl cleaner dispenser--is blocking the valve from closing properly.