I have just replaced the thermostat and the sensor right near it because if the trouble code that directed me to why the engine was idling rough, surging and temp gauge fluctuated. After two hours of the battery being disconnected and work completed, the engine was started. naturally it was rough at first. problem is engine light back on with same code telling me its the thermostat or sensor. further the engine still idles rough from time to time at a stop light. The temp gage is dead nuts 212 area and does not move anymore. How long does it take the computer to relearn it's paramters that were reset?