overheating stalling problems

I have a 89 honda civic lx and have changed thermostat, fluids, cap, and still overheats and stalls. Runs rough off and on. No codes are reading and ECU is ok.
Any suggestions?

Leakdown test. It will tell you if you have a bad headgasket, valves stuck open, or bad rings. If you dont really know cars very well, i suggest going to a shop and having them do one on your car.

waterpump, maybe.

I would guess waterpump, or your fan isn't kicking in. But that wouldn't explain the stalling, unless the stalling is a direct result of the heat somehow.

If you're not mysteriously loosing coolant (not leaking, but still loosing it), then it's not the head gasket.