2 things, I had my 2018 in for a simple warranty issue, and they updated the ECM flash. It now idles at 900 or 950. The other, I had this issue after I updated my intake to a stage 1. It ended up being I did not have the backing plate installed correctly to the Throttle body and it had an air leak. Once I removed the black bracket behind the backing plate and re-installed the backing plate, it ran fine.