Engineering group Weir said it expects fourth quarter profit to come in at the upper end of market expectations after a strong third quarter performance.The group, which supplies engineering services to the mining and oil & gas industries, said cost cuts and the weaker pound helped trading in the third quarter despite uncertainties in many of its markets. Analysts have forecast fourth quarter profit to be in the range of £151m and £171m."As expected revenue was adversely impacted by first half input trends, although operating results benefited from a greater proportion of aftermarket sales, the realignment of the cost base at a number of operations and a continued positive foreign currency translation effect," Weir said in a company statement.Net debt at 25 September 2009 was below levels at the end of June 2009 after strong operating cashflow.The group added that following the announcement of Keith Cochrane taking over as chief executive, the search for a new finance director is progressing.