My car is idling erratic when I'm in park and also the lowest my idle will go is 1100rpm. This is even after adjusting the idle screw to close, but the rpm still is high. In the past, is was around 750-800rpm.
Check for vacum leakages, PCV. Check the Fast Idle Thermal Valve (FITV). Remove the air hose fromm throttle body and use a cardboard to close the lower prt immediately inside the throttle bore to test idling goes down.
Check the IAC as well.
Check coolant level and ensure the hoses to IAC and FITV are not clogged.