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I have a Ford Focus 2005 Motor Zetec which presents the following fault, when I am in a tail with the air conditioning on when starting or starting the march, it could be someone help me that it will be the fault thank you

The revolutions clean the admission body and the Relay regulator to see how you are, test and Abyss.

Hello, when the compressor is underway the electronic control unit increases the opening time of the injectors so that the idle is stabilized to the same revolutions as if the air conditioning does not work. First before, you must have everything ready, spark plugs and no air entry into the admission, after it has been measured by the flow. The idle valve can be stuck or the Bi Pass duct, and do not let the mixture. The ´fallo of the valve should also affect the idle in cold without any engine load, either electro fans or air conditioning, I think that the idle valve is the first to inspect as Kikemec says, then the EUC or wiring can be the failure. All the best.