Air conditioning isn't cooling at red lights.

if your loosing compression it could be dirty valve guides or valves. could also be poor rings or a loose timing chain. have the compression checked when its happening.

you need to replace the capcitor

that may be the problem for compressor working for sometime

Are you saying the air coming out of the vents is not cold unless you are moving ? Or there is no air unless you are moving ?
And are you sure the radiator fan is running with the ac on ? Can you feel air being pulled thru the condenser ? What are the gauge readings with the ac on and the engine at idle ?

first make sure the cooling fan is turning on then flush out the condenser fins and raid fins as well

CHECK THE THERMOSTAT. THERMOSTAT IS THE ONE THAT SENSE THE ENGINE TEMPERATURE AND TURNS ON COOLING FAN WHEN THE ENGINE IS HOT.

The air conditioning condenser creates a lot of heat when the a/c is on. The cooling fan is supposed to run the whole time the a/c is on to keep it cool. If the fan isn't on, the radiator will absorb this heat and cause your car to over heat. You should also check your coolant level. So, it sounds to me like your cooling fan isn't working.

Sounds like your condensor cooling fan isn't working. It cools while driving because air is forced over condensor while driving. Tio prove this, place a box fan in front of the car and turn it to high. Watch it start cooling.

Thanks for choosing FixYa and welcome to the site. I wouldn't change the thermostat. Sounds to me that you are low on freon. Have you tried to add some to your vehicle?

Well let me tell you this.

2 days ago my a/c didn't put out cold air. It worked the next morning & evening and this morning and almost all the way home tonight.

My 2005 Tarus just did the same thing tonight, emissions light came on while I was going about 80mph. I got over to the right lane and slowed down to 60 and made it off the highway.

As I proceeded home it was acting like it would stall at the red lights but didn't, until I pulled into the driveway (lucky day?).

Bottom line is my emissions light is on and the car won't start.

I will update you asap., on my repair when i take it in tommorrow.

first thing get sombody to check all fluids in your car. if the red light comes on only with the air conditioning on then it seems to me insuffient cooling. i say this because your aircondiioning condensor fancy name for rad is in front of your actual engine rad and some times built in to the engine rad itself. have to tried stopoing at a red light with the airconditioning off?? does it still do what you say it does??
i really cant see the problem being the altenator because it only powers your blower motor and anythign electrical. you air conditioning is powered by a belt attached to the motor. hope this helps you.