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Q: Rough idle and no power - 2004 Ford Ranger

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I replaced the ignition coil and still does the same thing, hard to start and no power, 2 cylinders are not firing ?

My car has 136000 miles.
My car has an automatic transmission.

A: Hi and thanks for contacting YourMechanic. ...

Hi and thanks for contacting YourMechanic. Check the spark plugs and plug wires to the cylinders. Make sure that there is spark to the plugs.

If there is no spark to the plugs, then check the harness to the ignition coil for battery voltage. If there is no voltage, then check for any blown fuses. If the harness is good and the fuses are good and there is a good spark, then check the fuel injectors to the two cylinders. Check for voltage on the harness to the fuel injectors.

If there is voltage, then I recommend switching the injectors around to see if the problem changes to another cylinder. If the problem changes, then replace the injectors. If the problem does not change, then the cylinders have a problem internally. Check for compression and perform a leak down test to determine the condition of the cylinders. If you need further assistance diagnosing your engine, then seek out a professional, such as one from YourMechanic, to help diagnose the loss of power problem and assist with repairs.

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