The U.S. dollar was firmer in the upper 156 yen range Tuesday morning in cautious Tokyo trading, a day after Japanese authorities were suspected to have stepped in to push the Japanese currency sharply higher after its drop to a new 34-year low. At noon, the dollar fetched 156.72-73 yen compared with 156.30-40 yen in New York at 5 p.m. Monday. The euro was quoted at $1.0706-0707 and 167.78-81 yen against $1.0716-0726 and 167.33-43 yen in New York late Monday afternoon. Tokyo stocks were higher, led by exporters that were boosted by the yen’s weaker tone against the dollar. Solid gains in the t…