Low idle when put in gear

Hi Carlos,

More than likely this is the PCM not calculating the air/fuel mixture correctly because it is getting faulty information from one or more of the 3 MAP sensors that you have on this engine.

The ECOboost engine does not have a MAF sensor like traditional engines. It uses MAP sensors placed at various positions in the intake. The PCM uses this information to judge (predict) the amount of air that is coming into the engine and matches that amount with fuel to achieve the proper mixture so that the engine runs properly.

What happens is the PCV system on this vehicle actually will pressurize the intake system which will force crankcase pressure back up through the combustion chamber and out of the valves into the intake. This is not that big of a deal except for the oily residue that comes along with it. When this gets burned in the combustion chamber the residue will actually make its way into the intake and clog up your MAP sensors. Then the PCM is no longer getting accurate air volume measurements so it is not supplying the proper amount of fuel for a smooth running engine.

Most people complain of just a rough idle but when you are adding a load to your engine, more than likely the PCM is not adjusting or adding the proper amount of fuel to keep the idle correct.

I don't believe you have an issue with low idle, I think you just have a rough idle. Point being, who cares if it is idling at 500 RPM if it is smooth.

The best correction is two things. First disconnect the negative battery terminal while performing this procedure. Main reason is, it is safety first. Second reason is, disconnecting the battery will force the PCM to relearn the idle when you start the engine again. Basically, it wipes out the memory and it will relearn from the sensor readings.

Next, remove each MAP sensor, location attached. Then clean each of the sensors with Electronic Safe spray cleaner. Do not use brake clean or shop cleaner. This has a chlorine in it that will damage your sensor. Electronic safe cleaner can be purchased at any parts store.

Once these sensors are cleaned, reinstall them in the engine and reconnect the battery and see if the idle has smoothed out.

If this does not help, then we are going to need access to a scan tool in order to monitor the systems and sensors to see what they are seeing when you are in gear.

Please let me know if you have questions. This was a lot of info and I am happy to explain further if you want. Thanks

These are the best pictures I could find. These are not all out of your 2.0L but they are out of similar engines so it may look a little different but they are in these general areas.

Please tell me if you can't find them and I will see if I can get more detail for your specific engine.