stock 1.8 Miata - high idle

I replaced all nine coolant hoses and cleaned the TBI. Now my idle is 1900 rpm. 

What did I do?

Leave a vacuum line off/create a vacuum leak somewhere? 

If it were a Honda, there would still be air in the coolant line that goes to the fast idle unit.

I've looked over things twice. The TBI is returning to the stop.

Runs great, just idles high.

Sub-steps of "cleaned the TBI"? (and to be a bit pedantic, it's just a TB/Throttle Body; there's no Injection happening there on a Miata)

What I'm driving at is disturbance of any vacuum lines or an Idle Air Control (IAC) valve or its attendant hoses and wires.

There are a bunch of stories on various Miata forums about not cleaning the throttle body with aggressive solvents because it can remove some coating and cause high idle.  I have no idea if this is actually true or just an urban legend, but it's been around for a long time.

But yes, the most likely cause is that you forgot to reconnect one of the vacuum lines.  You might also want to reseat the electrical connector on the idle air control solenoid.