The airflow meter of Rover L series 2.0 engine is out of order. So, the car was a bit slow while it just started to run on first and second gear. Also while on motorway the fifth gear is almost unusable. I disconnected the airflow sensor. It was almost the same. I then reduced the link on my waste gas and it gives the engine more power and more boost, but it's making smoke. What should I do to compensate it?