Oil prices came back slightly higher Wednesday following a steep fall in the face of warnings from world leaders that record highs were challenging economic growth, dealers said.New York's main oil futures contract, light sweet crude for August delivery, rose 11 cents to 136.15 dollars a barrel. The contract tumbled by 5.33 dollars to close at 136.04 at the New York Mercantile Exchange on Tuesday. Brent North Sea oil for August delivery rose 21 cents to 136.64 following a plunge of 5.44 dollars to 136.43 Tuesday in London.