Not sure what you're asking, but dif this is happening all the time, you might have a dual air control system. You can adjust the temp for the passenger and the driver, and the control may be faulty.
Moisture under the distributor cap from Windy D
You need to first check that you do not have any vacuum leaks and then check the a/c / heater door operations, if all are working then its possible that you have a slightly clogged heater core.........
The weep (overflow) hole cannot be closed on a 1998 Pontiac Grand Am 2.4 liter. This hole is there so that the engine can let off pressure when things get a little too warm. It keeps the engine from overheating.
Temp blend door actuator malfunction.
There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.
Replace the fuel pressure regulator, it is leaking fuel past the diaphragm and flooding the motor.
Some 99 Grand Prix vehicles will shift hard when it is warm. Not all of these vehicles will do this.
My mom had the same problem and we added freon and it blows very cold all over now.
Sounds like an electrical problem. Only way to determine is to take it to a reputable shop and have them dignosis the problem.
Hey kenneth==It is the directional door not operating properly. It may be a problem with the controler. GoodluckJoe
heater core could be plugged, also check for low coolant
I have the same problem and I was told, by the dealer, that the fuel pump module isn't holding the correct pressure after a "warm soak" and needs to be replaced to the tune of $1,000.