Is the "for" implied in "caut"?
I think a more direct translation would be "I seek ...," and in that case you wouldn't use the word "for."
Why we need "for"? Only search isn't enough?
That's because the "for" is needed in English. If you "search someone or something" it has the meaning of frisking someone/something, like at the airport or at the police or if you search a dog for fleas.
sound is disgusting (unde a fost lui?)