I recently replaced my serpentine belt as preventative maintenance. Since having it replaced, my car is now idling higher than it was before.

The first day back I started my car and it almost died. The rpms dropped low and the car almost died. It has not done this since.

After that initial start my car has been idling high. I am familiar with the high rpms on cold starts that settle down after a minute but even when my car is warm it will idle around 1100.

I have cleaned the throttle bodies last year with no issues since then. So I am fairly certain this is not a dirty throttle body issue.

Will changing the belt in anyway affect the idle or is the process of changing the serpentine belt indirectly affects idle?

 

What is the car idling at while in D? Should be ~700ish

 

The car idles around 600-700 in D which is correct. No issue when its in Drive.

The issue only persists when the car is in PARKED. Then it idles at 1000-1100 rpm after warmed.

I did the ECU Throttle relearn with no luck.

Car has no CEL light or any other issues. Only one is TPMS on winter wheels not calibrated yet. Just put them on.

The car does not feel right with this high rpm hoping for assistance.

 

new serpentine belt and idle speed have no correlation.

You stated the car has no CEL or any other issues. I would not worry about it.