Q: Idles Low and Almost Stalls

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My vehicle has been idling at 500 and below and is bucking or sputtering when at red lights or in park. I have a faulty coolant sensor that yet to be replaced as I would have to replace the entire coolant reservoir. Would this sensor be causing a low idle issue or what else could be causing this?

My car has 110000 miles.
My car has an automatic transmission.

Hello there. Sometimes when the coolant system is experiencing a fault as you’ve indicated, it creates additional drag on the motor; which can reduce engine RPM significantly. However, this is typically when the water pump is faulty or damaged. It is possible your TPS (throttle position sensor) is faulty or simply dirty. It could also be dirty fuel injectors, throttle body or mass air flow sensor. I would recommend having a professional mobile mechanic come to your location and complete an engine RPM is low inspection, so they can pinpoint the source of this issue and recommend the right repairs.

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