* TSX up 45.23 points, or 0.3 percent, to 15,338.20
* Touches 15,350.76, highest since June 29
* All 10 of the TSX's key groups were up
TORONTO, Sept 20 (Reuters) - Canada's main stock index rallied to an almost 12-week high on Wednesday with Air Canada and energy stocks driving broad gains as investors awaited the outcome of the U.S. Federal Reserve policy meeting.
Six of the 10 most influential gainers on the index came from the energy group, which climbed 1.1 percent. The sector benefited from higher oil prices, which were on course for their largest third-quarter gain in 13 years. Natural Resources CNQ.TO rose 1.7 percent to C$41.16, while Encana Corp ECA.TO advanced 1.9 percent to C$13.35.
Air Canada shares AC.TO surged 7.4 percent to C$25.05 after several analysts raised their target prices and ratings on the airline following its update of its 2018 to 2020 financial goals. 10:13 a.m. ET (1413 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE rose 46.9 points, or 0.31 percent, to 15,339.87, with all 10 of the index's key groups higher.
The index at one point touched its highest level since June 29 at 15,350.76.
Still, investors' focus was on the Fed, which was due to unveil its latest policy decision and forecasts this afternoon.
The financials group gained 0.2 percent, and the industrials sector rose 0.7 percent.
The materials group, which includes precious and base metals miners as well as fertilizer companies, added 0.2 percent.
Advancing issues outnumbered declining ones on the TSX by 156 to 76, for a 2.05-to-1 ratio on the upside.