Check the motor mounts.
Check the idle, crankshaft and camshaft sensors.
check your idle air control valve and/or your TPS
could it be the thermostat or the fan itself?
More than likely it's your Idle Control Valve.
what does idle funny mean? Does the whole car shake? (upper engine mount collapsed) Or does the engine shake/misfire? (Intake manifold gasket)
because that's kind of a big engine
Might want to check your idler sensor.
There is a bad ground cable.
it has a low idle. Can also be a vacuum hose leak.
miss alignment of tires