Different terrible car engine may start form the car engine from the problem of the car engine P2126 Code. You should not let this happen. You need check the car engine and fix the problem. This task will be done by an automobile engineer who knows well his duty. So, let him to do this. Do not drive the car if the car engine is not ok yet. You must fix the car engine by the expert automobile engineer. When the car engine is ready, you should test the car by a test drive. If the car engine is fully ok, then accept the car from the car engineer.