Code P0303 means that there is a misfire detected on cylinder #3. This could becaused by anything from a worn out spark plug to a blown cylinder head gasket, a faulty fuel injector, a bad ignition coil, or a leaking intake manifold gasket. I have also seen this type of code caused by clogged-up EGR ports in the intake manifold on certain engines. "Freeze Frame Data" stored in your Engine computer along with the fault code is designed to help identify what engine conditions (high speed/slow speed, heavy load/light load, etc.) are producing the misfire. This helps a lot in identifying exactly what is causing the cylinder to misfire.
One way to eliminate some of the possible causes is to swap parts with another cylinder to see if the code changes.
If you have "Coil-On-Plug" ignition, you can swap the coil on #3 cylinder with the coil on #4 Cylinder and swap the #3 spark plug with the #2 spark plug. Then clear the codes and drive the car till the Check Engine (or Service Engine Soon) light comes back on.
If it still gives you P0303, then it is not being caused by the plug or the coil. It could be any of the other possible causes listed above.
If it now gives you P304, replace the bad ignition coil that is now on #4 cylinder.
If it now gives you P302, Then replacement of all the spark plugs is recommended.
P0303 is a misfire in cylider 3. This is almost always an ignition coil in this car. I would swap out all 8 with Motorcraft coils as well as spark plugs. If one is going, the others arent far behind and one bad one makes the others work harder.
A code P0303 may mean that one or more of the following has happened:
1,463 views
Usually answered in minutes!
×