a/c not cooling on idle

The fan has to kick in to pull air across the condenser when you are idling and no moving very fast. Is the engine fan coming on at all?

 

your compressor is shot more than likely, get the part yourself and go to a shop and save a few bucks. you will have to pay for a full recharge on your freon tho.

 

What is your high side pressure when this occurs?

 

Mine is the same way. Someone the other day told me it had a bad High Pressure switch. For what it is worth. Mine freezes me out of the truck when I am rolling down the road. I can set the engine on High Idle and run the engine fan on Manual and it still won't work when idling!

 

^^ terrible advice.

What are the high AND low pressures at idle?

When I clean a condenser, i soak everything in Power Purple for five minutes, then rinse it all at with low pressure from the engine side through the grill.

Are the condenser fins bent? That will restrict airflow and the low pressure side to read high on the guages.

Make sure the fan is on. I have to turn mine on manually, then I always forget to turn it off when I hit the highway

 

Replace condenser
Verify proper charge for your system (over charge will drive both low and high side pressures up and both of yours are high)
Verify proper engine fan operation
You didn't mention the evaporator filter or cleanliness of evaporator?
How is your heater set up? Blend door or coolant control valve?
Consider installing manual shutoff valves in your heater hose.