hey scotty!
I have an 87 mustang with the 2.3 I4 and it idles at about 1,200rpm and stays there even after letting it idle for about 10 minutes and was wondering what it could be. thanks!

check for vacuum leaks first, if not that, try this video https://www.youtube.com/watch?v=NWCKvU2FmDc&t=117s

alrighty thanks scotty