Q: Car runs rough sometime an engine diagnosis says I have a misfire in three of my six cylinders sometimes car runs smooth other tim

Hello, thank you for writing in. When it comes to a misfire on several cylinders, the vehicle is likely struggling with compression. If the issue was fuel or spark related, the engine would have a misfire code on all cylinders. You are going to want to look into a possible head gasket issue, catalytic converter issue, or other issue pertaining to the compression. There are several tests you can do to check for vacuum leaks, or a failing exhaust component. If you have any additional codes from scanning the vehicle, use those to help direct you towards the problem. For more help resolving the issue, contact our service department to schedule an appointment.