Engine idling erratically, interior thermostat not working. Tried replacing the alternator and then replacing the coolant temperature sensor. Nothing is working to fix this problem. Also, tested the grounding wires to the coolant thermostat sensor which did nothing in fixing the thermostat reading inside the car on dash board. What else could be wrong with it?
What do you mean by interior thermostat not working? Do you mean the temp gauge is not working? If gauge is not working usually a simple software update to the engine control module will take care of this issue. It also may or may not help with the idle issue as well. What I would do about the idle is have the throttle body cleaned and pcv system cleaned out. Remove the ETM and ECM fuse while doing the cleaning so that both systems reset and relearn on there own. Hope this helps you out.