Hello. I have a 2009 Subaru Impreza 1.5 Elegance car. I have owned the car for 4 years. I have been experiencing a problem for about 3 months that I cannot solve. The car does not have any issues when driving? on flat ground or downhill. However, when going uphill, it experiences power loss regardless of the incline. I used to drive up the same hill on my way home 3 months ago in 3rd gear at 80/70 km/h speed. Now, I have to shift between 2nd and 1st gears and climb at 20/30 km/h speed. I have tried adjusting the valve timing, replaced the 2nd oxygen sensor, checked the catalytic converter, replaced the 1st oxygen sensor, and replaced the airflow meter. Furthermore, when I read the fault code from the car, it gives the codes C0109 and C0140. It does not provide a different code.However, there has been no change, and the car still behaves the same way. What could be the problem? - If anyone has a solution, please share it in the comments. Have a nice day.