My '00 NB has lost its umph. Intermittent power loss when I pull away from a standing start. Car is idling ok but momentarily RPMs drop, it almost conks out, then re-groups and idles ok.

Background: A week ago I threw an alternator/water pump belt and in the time it took me to get into a gas station (5 mins?) the temp gauge climbed to max. I shut it off with no water/coolant leaking but the engine had definitely heated up. When I got the belt put back on it began its rough running and threw a CEL. I forget the code number but it was for spark plug wires . I replaced those and the plugs (and got rid of the CEL) but the rough running hasn't gone away - in fact it's gotten worse and yesterday it threw another CEL. I haven't had time to get a code on that yet.

I'm thinking this is electric and related to the engine overheating. Maybe a bad coil? Any help would be appreciated.