How to fix a floating idle on a Toyota 4A-GE motor

[Homem Bomba]

If it's intermittent clean the contacts, if it remains I would take out the throttle body and clean the passages that run coolant to and from it; they adjust the idle on cold start by pushing a spring with varying force by expanding a cell filled with a substance like the wax in a thermostat. If the channels become clogged with rust, the coolant wouldn't flow correctly and you would get an erratic idle.

The idle air valve may also be the culprit, but before moving to the hard solutions, try burping the cooling system. Open the radiator cap half way so that it stays on the rad but does not seal, run the engine until the coolant starts to leak out naturally, and pinch the radiator fluid hoses while you do it to remove any air.