My 2003 Honda Civic 1.7L 4 cyl has some performance issues?

The symptoms I'm experiencing are sputtering, basically it almost sounds like an 80s vehicle… It idles rough, and the temperature gauge also goes up during idle for an extended period of time… Yes I just had my cooling system topped off. As far as rough idling, it only idles rough. Once I start driving it seems to dissipate and drive like normal. I've gotten several opinions so far. Some say spark plugs, some say fuel filter, some say injectors, or could it possibly be the idle control valve? I'm so confused what it could be. I just want to get to the bottom of this. Anyone have any ideas?

It's almost 15 years old. It's going to have some performance issues. A qualified mechanic can tell you what the problems are.

Did you pull the plugs out and see what they look like? When was the last time they were changed to start with?

Fix the over heating problem first.

When was the last time they were changed to start with