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Q: Car idles fast when stopping.

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Hi all. I have a Ford Focus ST170/SVT and whenever I pull up to a stop the car idles to around 1800rpm for about 3-4 seconds then drops to normal idle around 1000rpm. I have replaced the idle control valve, cleaned the MAF and throttle body and checked for vacuum leaks by spraying brake clean while idling with nothing found. I also have an issue with the car missing at higher revs and have removed the Intake Runner Control Module and cleaned the contact and tried to fasten the spring/cable inside as it was loose. I am about to check it again as it has reverted back to occasionally missing again. Your thoughts and advice would be greatly appreciated. Mark from New Zealand.

My car has 74000 miles.
My car has a manual transmission.

Hi there:

It looks like you’ve inspected all the normal suspects of a high engine idle situation. One issue that pops up occasionally; especially on early 2000 period cars, trucks and SUV’s is due to a faulty radiator coolant temperature sensor. When the sensor detects that the engine is running cooler than it should, it can trick the ECM into increasing the engine RPM as it does in order to warm up the vehicle. This is why the idle will be higher for a few seconds after you come to a stop. However, it can be multiple other electrical issues as well. The best way to know for certain is to have one of our local YourMechanic technicians complete an inspection in regards to you engine idle at high speed.

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