I just saw the example "Jag letar efter pojken", which meant "I am looking after the boy".
So, why would "Jag letar efter en restaurang" not translate to "I am looking after a restaurant"? (maybe it does, but the answer wasn't accepted)
In English, "I am looking after a restaurant" and "I am looking for a restaurant" have two very different meanings; the first implies you are possibly taking care of the restaurant on behalf of the owner, while the second implies you are simply looking for a place to eat.
I would translate "I am looking after the boy" to "Jag tar hand om pojken" or "Jag passar pojken". (if you want to tell that you are babysitting for example). "Jag letar efter pojken" can only translate to "I am looking for the boy", after would be incorrect in this case. Swedish speakers often make incorrect translations into English because e.g. "leta efter" and "look after" sound similar.