I have a 99 legacy outback 2.5 5 speed . When the car has set in cold temperature it does not want to start. i have to crank and crank and hold the gas pedal to the floor in order for it to start. once it is warmed up it seems to be real sluggish and then just takes off. also it wants to idle low around 700 rpm and the exaust smells rich. it does not use oil. the exaust sounds like it churps or has a miss. the engine sounds smooth .the car has 150k miles on it. does anyone have any suggestions.