When car stop at a traffic light, sometimes it will hesitate like it want to cut off, have to step on the gas to keep it from cutting off. Car sounds a little rough also, this started after I had a thermostat put in.

 

When my car stop at a traffic light, sometime it hesitate like it want to cut off, have to step on the gas paddle to keep it from cutting off. I just had a thermostat put in a few days after when this hesitation started.

 

Is the temp gauge working? What does it read?
Did you replace the t-stat or did a shop?