By DEE-ANN DURBIN, AYSE WIETING and KELVIN CHAN ISTANBUL (AP) — For months, Istanbul restaurant Tarihi Balikca tried to absorb the surging cost of the sunflower oil its cooks use to fry fish, squid and mussels. But in early April, with oil prices nearly four times higher than they were in 2019, the restaurant finally raised its prices. Now, even some longtime customers look at the menu and walk away.