Q: Cold start idle isn't working and poor fuel economy!

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Car idles at 1000 rpm constantly and on cold starts will not idle high for warm up.When ac is turned on idle drops instead of raises plus terrible fuel economy with new full tune up!????

My car has 108000 miles.
My car has a manual transmission.

Hi Jason. Thanks for the question today. It is quite possible that you have a faulty mass air flow sensor (assuming it was not replaced during your recent tune up), damaged idle control valve or perhaps even a loose or damaged vacuum line. Each of these components can be the source of the inconsistent engine idle and the poor fuel economy. It’s also possible that other fuel system or even ignition system components could be damaged, so it might be best to have a professional mechanic complete an onsite inspection to determine the reason you’re having these problems.

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