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go for 4th as said above. around town will always give you bad economy try downshifting to slowdown too the less brakes you use the better your fuel
lol wut? downshifting = more revs = more fuel. If your pulling upto a set of lights in a manual and you use the gears to slow down instead of brakes you will use more fuel, unless you mean something else.
btw if your just cruising and the car isn't towing/struggling/going up a hill, 5th/6th gear will be fine.