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.
Your hands are likely to be splashed a little by the dirtied water in the toilet bowl as you strive to unblock the toilet. Plunge the toilet with a plunger. The vast majority of unblocked toilets are caused by a blockage in the bend in the pipe just behind the toilet itself.