This is the second time that my car did this. Just when it get warm the RPM get slower to almost it feel that it is going to shut off, ant the same time the temperature gauge went up to 3/4, when I blow air to the inside it got cold little but I still didn't know what the cause the problem. Recently I changed the distributor.

Any advice would be appreciated.

 

silly question but have you checked the coolant level

 

This is the second time that my car did this. Just when it get warm the RPM get slower to almost it feel that it is going to shut off, ant the same time the temperature gauge went up to 3/4, when I blow air to the inside it got cold little but I still didn't know what the cause the problem. Recently I changed the distributor. Any advice would be appreciated.

Yep, the engine temperature is normal, I recently changed the cooling, and the engine was not that hot at all. I felt the pipe to see if there is a pressure from the thermostat to make sure it is opening. The pressure was equal on both sides of the pipes coming in and out of the radiator.
I think there is no problem with the car, I thought after checking the engine when this happened that the reading was wrong. The engine was not hot to what the heating gauge said so.