Q: My Camry 2001 stalls when I stop on lights and take my foot off the gas pedal and it also evaporates coolant but never heats up?

Hi, My Camry 2001, 2.2L, 4 Cyl, Auto with 265000 kms on the clock stalls when I take my foot off the gas pedal while on lights or elsewhere. When I press the pedal again then it's all ok and has good pickup. While reversing at low Rpm and Speed the car continuously stalls and gives a jerky ride but the engine never goes off. Before, my car had faulty spark plugs and I drove for a week with faulty plugs as I was so busy so couldn't replace them instantly, but now I installed new spark plugs the BOSCH ones. The spark plug problem is now fully resolved and the car is not misfiring or sounding like crackers but the stalling problem continues as I stop on lights or elsewhere with my foot off the gas pedal. If I put my car on P or N on traffic lights and give it a bit of juice then it won't stall. Secondly, the car evaporates coolant too quickly in about 40 kms ride but never heats up. Ive checked that there is no prominent leak in the radiator and it's all good like new. Plz advise ? to do?

My car has 265000 miles.
My car has an automatic transmission.