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Q: My car idles very roughly on first start up of the day

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Every day on the first engine start up of the day my car idles very roughly as if the engine is about to die and the Rpms start to jump. This used to happen very badly only when it's cold outside, but now it's starting to happen also when it's not cold. To make the very rough idleing stop I have to press the gas lightly until the engine heats up and then it's all good. Once the engine is heated the car drives very good. Very smooth. I have been getting lean fuel mixture codes and misfire codes. I Don't know if this is a bad coil pack or something else. I also recently changed the spark plugs.

My car has 123000 miles.
My car has an automatic transmission.

The lean fuel mixture codes may explain everything. They frequently occur when there is an air leak in the intake system somewhere. Your engine has an Air Flow Meter (MAF) that measures the air going into the engine. The ECU uses this information to decide how much fuel to inject. If there is an air leak, or of the MAF is bad or dirty, air will get into the engine without being measured and so there won’t be enough fuel delivered. This will lead to poor idle and misfires. You can check under the hood for damaged or poorly connected hoses or air boots, but if you need some help with this you can contact Your Mechanic. They will send a technician to your home or office to check out your BMW and tell you what it’s going to take to solve your problem.

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