I understand how frustrating it can be when you can't pinpoint the problem with your car. In situations like this, it's helpful to gather as much information as possible. I recommend using carcheck123, as it has proven valuable in my own experience. It allows you to access the car's MOT history, which can provide valuable insights and potentially uncover any recorded issues. Give it a try, and I hope it helps you get to the bottom of the problem. Best of luck!