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Q: My car does not idle until it is warm. Can you tell me what's wrong?

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After doing my heads I put every thing back started the car and came up with a problem it does idle only when the car is warm it's low idle can you tell me what's wrong

My car has 19800 miles.
My car has an automatic transmission.

A: Hi there. Check the engine for any vacuum ...

Hi there. Check the engine for any vacuum leaks and see if all the sensors are plugged in. Take a vacuum gauge and put it on a vacuum line to the manifold. Check to see if the engine has 17 mg to 21 mg of vacuum. If the engine is less, then there is a vacuum leak and it needs fixed. If the vacuum is good, then look at all of the sensors and make sure that they are all plugged in. Also, make sure that the idle air control valve (IAC) is plugged in to vacuum and is working. If everything is working correctly and there is vacuum, then there is a possible issue with the IAC or the mass air flow sensor (MAF). If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from Your Mechanic, that can assist you with the engine idle not staying up during startup.

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