2006 Buick Rainier 2.4L 6cyl. AWD
P0449, P0128, P0506, P1400
In the past few months my car lacks power when accelerating. It takes longer than usual to get up to speed. The EVAP codes and the check engine light have been on for over 5 years without any issues. Occasionally when the light goes off, I get the Emissions Test done (every other year) and pass with flying colours. Last Emissions Test was June 2017. Car starts up fine. What could be causing the sluggish acceleration?