Air conditioner runs hot after a few minutes sitting idle. get cold while driving but goes hot after i stop or come to a red light

Check your coolant level when engine cold, low level coolant does not circulate very well at idle and will cause poor heating,at higher RPM water pump turns faster to help circulate.
press the helpful button,

check and make sure the radiator is full of antifreeze take off the radiator cap and top off the radiator then take your hand and cover the hole where the cap goes and squeeze the top radiator hose a few times to help it go down that way if there is a air pocket somewhere it will help push it out when you thank your done top off again and replace the cap and try

If you have a viscous fan hub have it replaced as it is not working. The problem you have is that the engine is not driving the fan to draw air through the radiator when idling so the engine overheats . When moving the air flow from driving cools the radiator and so the temp goes back down. If you have electric fans have the codes read to find the fault or check why the electric fans are not working.

I actually had to replace my EGR valve and the gasket. I clean the valve well and reused both. I don't think the gasket sealed well enough though. So I went ahead and got a new valve, gasket and changed them. It runs a lot smoother now.

check coolant level could be too low allowing air in the cooling system causing air pocket in engine around the engine coolant sensor.coolant sensor needs to be in hot coolant so it will cause the cooling fan to come on at a set temperature.make sure coolant correct level and the coolant level in the cooling overflow jug should be at full cold mark.the cooling overflow jug should never be empty,if you see empty cooling overflow jug air got in the cooling system so make sure when engine cold every time raise hood make sure cooling overflow jug coolant level at full cold mark.if jug stay empty you have cooling leak.so replace radiator cap,if coolant level all good,i would replace the engine coolant temperature and thermostat.when your car come to a long stop or driving along long line of slow moving traffic the engine coolant blower motor should running if not have vechicle code scan for faulty coolant fan motor control module.or ecm problems.

It may be that you have a vacuum leak. In some models of GM cars the AC controls are controlled by vacuum. At idle the vacuum may not have enough suction to hold a control in the desired position. When the situation happens, place the transmission in neutral and increase the RPM. If the AC blows cold then the vacuum may be the problem.

first problem is simply your radiator cooling fans (there tow of them) are not working my be due to a fuse and/or relay those fans are turning with ac on even if your car is cold and turns when radiator gots hot even if ac is off
so when your car is hot open the hood and just take a look are they running or not they just in front of radiator

your ac compressor is freezing up try not putting it on cold all the way. put thermostat towards the red jus a lil but still on the cold side to see if that helps

jtg

The refrigerant may be low, also could be that the a/c compressor is going out. Have it checked