"I was looking for my wallet."
Translation:Jag letade efter min plånbok.
If you say min plånbok, it's unambiguously your own wallet. If you say just plånboken, it could be some other wallet known to the listener too. But we often use the definite when it's obvious from context that we're speaking about our own one, so both ways are fine here.
You can't really use "letade för". Letade efter is the correct way of using the translation of looking for. Although you can say "Jag letade där för att hitta plånboken" (I was looking there to find the wallet) But it doesn't mean the same thing as you can see.
Quite confusing i must say (as a swede) since the word "for" is directly translated into "för".
You are doing a literal translation but it's grammatically wrong. "I was looking for" in swedish translates "jag letade efter" or in some dialects "jag tittade efter". If you remove the "var" it becomes "i'm looking for my wallet".
If it makes sense :) /Native speaking swede
I'd just like to add that the grammatical reason is that Swedish lacks a proper continuous, so "am looking" and "look" both translate to the same thing - and that reasoning goes for other tenses as well, such as "was looking" + "looked". :)