How To Find Ford Focus Misfire

How To Find Ford Focus Misfire


Engine misfire is never a fun time, especially when you have it in your new Ford Focus. Although random engine misfire can be difficult to track down in a larger engine, it’s not as hard when you have a Ford Focus Misfire condition. Today I’ll be showing you how to test for Ford Focus Misfire in a 2013 Ford Focus by testing your ignition coils.

This test vehicle is a 2014 Ford Focus ST with the 2.0 liter turbocharged Ecoboost engine in it. Because there are no traditional “spark plug wires” used in your coil on plug setup, this minimizes the work you have to do. Testing for Ford Focus misfire is also much easier due to the fact that you are working on just four cylinders.

How To Find Ford Focus Misfire p0300

This test is meant to uncover a dead cylinder, or one that isn’t firing as properly or as strong as your engine would like. Using this method you can find which cylinder is causing your misfire, and replace the ignition coil if necessary.

Discovering engine misfire through engine balancing

Engine balance testing is very simple and easy to do. It involves unplugging your spark plugs or your fuel injectors one at a time, until you can determine the dead cylinder. Doing this on a 4 cylinder engine like the one in your Focus can be easy to do. Simply unplug the fuel injectors while your engine is running.

When you unplug a fuel injector your engine should stumble and come close to dying. If you unplug an injector and your engine idle doesn’t change much, this is a sign that the cylinder in question has an issue.

This is also much easier to do because your engine’s exhaust is facing rearward, which makes disconnecting the fuel injectors much easier.

Testing your Focus ignition coil for power

Once you have your engine cover removed, you can easily gain access to the coil on plug ignition setup. As stated previously the coils are connected by a three pin engine harness. There’s a power wire, ground wire and a switching wire which tells the coil to fire when the Focus engine computer sends the right signal.

Ford Focus P0300 Trouble Code – Test your Ignition Coil 2

To begin testing unplug the problem cylinder in question. You will be using a digital multimeter to test for power and ground. With the ignition coil unplugged, you can begin testing by checking for the power signal. This part of our Ford Focus Misfire guide should be performed with the engine off, and the ignition key turned to the “ON” position.

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The first pin you will be checking is PIN A on the engine harness side of your Ford. This should return a 12 volt power signal with your key turned to the “ON” position. If you have power here, check PIN B next for the low reference ground signal.

If you have power and ground at both wires, chances are you have a bad ignition coil. These are “dummy” coils which means they are not smart and do not do anything other than amplify and deliver spark power.

Remove your ignition coil on plug and install a new replacement ignition coil. You can then use any OBDII scan tool to clear any stored trouble codes. Have any questions about our Ford Focus Misfire guide? Leave us a message below and let us know!