So a while ago before winter came, I was having idle issues after the car was warmed up and sometimes would through a service engine now light on the dash. Would shut the car off turn it back on and would be fine. Winter came, it wasn't doing it. Now it's back to being warm my car high idles all the time. Come to a stop and it will hover around 1500-2000 rpm sit there for like 3-10 seconds then come down to normal idle. But you can also feel it while driving, the hanging idle will affect shifting. All the vacuum lines seem to be plugged in and no leaks. I've had the throttle body replaced 3 times already for the issue. Fixes it for a small period of time then back to the high idle. What does everybody think it could be. It is a 2016 focus st with 16k miles on it.