{"id":6754,"date":"2021-03-11T06:29:59","date_gmt":"2021-03-11T06:29:59","guid":{"rendered":"https:\/\/notsealed.com\/?p=6754"},"modified":"2023-07-27T03:22:32","modified_gmt":"2023-07-27T03:22:32","slug":"ford-focus-rough-idle-with-no-check-engine-light-fix-diy","status":"publish","type":"post","link":"https:\/\/notsealed.com\/ford-focus-rough-idle-with-no-check-engine-light-fix-diy.html","title":{"rendered":"Ford Focus Rough Idle with No Check Engine Light Fix DIY"},"content":{"rendered":"\n

My 2003 Ford Focus 2.0 has developed a rough idle without a check engine light (CEL). This is an easy fix that anyone can do themselves with a few simple tools.<\/p>\n\n\n\n

There are eight parts to check that can cause a rough idle with your car.<\/p>\n\n\n\n

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  1. Dirty Idle position valve – (IAC or IPV) very common<\/li>\n\n\n\n
  2. PCV valve or faulty hose – common<\/li>\n\n\n\n
  3. Vacuum leak<\/li>\n\n\n\n
  4. DPFE fault- very common<\/li>\n\n\n\n
  5. Mass Airflow sensor dirty or failed – common<\/li>\n\n\n\n
  6. The throttle position sensor is faulty.<\/li>\n\n\n\n
  7. Spark plugs, leads, and coil.<\/li>\n\n\n\n
  8. Head gasket Coolant leak into a cylinder – Expensive repair not common.<\/li>\n\n\n\n
  9. Bad Vibration caused by worn engine mounts.<\/li>\n<\/ol>\n\n\n\n

    Each will cause your car to splutter in the idle position. Usually when your car warms up the idle will improve.<\/p>\n\n\n\n

    Ford Focus has a history of developing cold rough idles. This is a well-known fault that you can repair yourself. Don’t take it to the mechanic, it will cost you hundreds. Fix it yourself. So let’s go over how to repair each of the 8 idle faults.<\/p>\n\n\n\n

    1. Car idles rough but drives smooth fix.<\/h2>\n\n\n
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    \"Car
    2003 Ford Focus Idle Control valve removal and cleaning<\/figcaption><\/figure><\/div>\n\n\n

    This is a common problem with older cars. Because the car idles rough but drives smooth points to an air\/fuel mixture problem.<\/p>\n\n\n\n

    The first part to check is a device called the Idle Control Valve (ICV) (IAC) or Idle air control valve. This little air solenoid will open and close the air mixture going to the engine during an idle condition.<\/p>\n\n\n\n

    The problem is over time carbon and other dirt particles get stuck in the Idle control valve causing the valve to stop working in either the open or closed position.<\/p>\n\n\n\n

    If it is stuck in the closed position you will get a rough idle, engine shake, and the car may even cut out and stop. If the Idle control valve is stuck in the open position you will get a fast-revving engine in the idle position. Both conditions are not good but will cause the car to run smoothly when you start driving fast.<\/p>\n\n\n\n

    Another problem could be worn motor mounts. It is best to clean the Idle control valve first to see if that fixes the shake. Motor mounts can then be replaced if the engine shake continues.<\/p>\n\n\n\n

    Ford focus rough idle fix<\/h3>\n\n\n\n

    To repair the Idle control valve you can either repair it or replace it. I prefer to repair the valve as it only takes a 1\/2 hour to remove the valve and clean it out. It is easy with a second person to help you.<\/p>\n\n\n\n

    Start by removing the MAS airflow sensor cable. The electrical cables are clipped into place so press down the tab and remove the electrical socket.<\/p>\n\n\n

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    \"Ford<\/figure><\/div>\n\n\n

    Take apart the air filter box and tubing to the engine throttle valve.<\/p>\n\n\n

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    \"Ford<\/figure><\/div>\n\n\n

    Remove the PCV air hose to give yourself more room to work.<\/p>\n\n\n

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    \"Ford<\/figure><\/div>\n\n\n

    Pull out the electrical connection clip that is attached to the idle control valve. It is tucked behind the manifolds and the engine.<\/p>\n\n\n

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    \"Ford<\/figure><\/div>\n\n\n

    Use an 8mm socket to undo the 2 bolts. There is not a lot of room so if you are having trouble you can jack the car up and come up from underneath. I ended up using an 8m ring spanner from under the car to undo the bottom bolt.<\/p>\n\n\n\n

    Clean the idle control valve using carburetter cleaning solution spray. Keep the ICV in the upright position so that the dirt runs out of the air holes and not into the electrical solenoid.<\/p>\n\n\n

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    \"Cleaning<\/figure><\/div>\n\n\n

    Use a flat-blade screwdriver to push the idle control valve up and down. make sure it moves freely. Leave it out to fully dry for 1\/2 hour before reinstalling.<\/p>\n\n\n\n

    Testing an Idle control valve.<\/h3>\n\n\n
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    \"Test
    Testing the Idle control valve with a fluke multimeter.<\/figcaption><\/figure><\/div>\n\n\n

    Once you have cleaned the idle control valve with carb cleaner be sure to test that it moves freely. I like to use a flat blade screwdriver to move the plunger up and down. It may only move 5mm this is normal.<\/p>\n\n\n\n

    I also like to test the Idle air control valve with a multimeter. Set the multimeter to ohms and put the probes onto the coil wires. You should get a resistance between 7 and 20 ohms. The idle control valve for the 2003 Ford Focus measured 9.6 ohms so the coil is fine.<\/p>\n\n\n\n

    If you are reading 0 ohms you have a short circuit and it will need to be replaced. You can get a new Idle control valve for the Ford Focus AC504 from most good auto parts stores. They are cheap to replace.<\/p>\n\n\n\n

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