1996 jimmy that overheated and the thermostat was changed and now it idles rough There is no water in oil or the oil isn't cloudy so I don't think the head gasket is blown the check engine light is on?

I would try a quick cheap fix first. Disconnect the battery and let it sit for 15 mins and rehook. You may have cooked the ECT (Engine coolant Temp) sensor ( are the fans running when cold? or The IAC ( Idle Air control) sensor may be bad or The TPS ( Throttle Position Sensor) may be bad or your throttle body could be dirty Overheating may have thrown these sensors out of range.