I have an engine light on and hard codes ran. Bought the parts and went ahead and got plugs for it. Changed the plugs and now the temp gauge doesn't work and it runs rough as hell. Any ideas of what may have happened?
I've changed the 02 upstream sensor, coolant temperature sensor, plugs, and thermostat. Car running rough and temp gauge isn't working and traction control won't engage. I'm currently resetting the computer by unhooking the negative pest from the battery for 30 mins. Anything else I can do?

 

What codes are you getting?
Have you had the battery & alternator checked?
Without knowing anything else, your symptoms have me thinking you have low voltage while the vehicle is running.