alanb1

hi,have just bought a 98 2litre galaxy aspen 73,000 miles.when accelerating and changing, gear revs increase by about 500rpm. also power seems poor generally[wouldn't hold a candle to my old diesel espace)it will pull better in surges then drop back again.is idling at 1100rpm also the engine temperature is not going into the normal range will be fitting a new thermostat,but dont think problems are all down to that.i strongly suspect an air leak i,e. vacuum pipes or inlet manifold.engine sounds sweet as a nut no rattles or knocks,no smoke from the exhaust i would appreciate any comments, suggestions regardig this problem look forward to seeing your comments. Alan