'95 mercury sable starts and stalls

I have a 95 merc sable that runs like a gem, until recently. I’ve never had to do anything at start up except turn the key. But recently, especially now that our nights are dropping below 60, when I turn the key it starts and immediately stalls. In order to keep it running I have to hit the gas immediately after it starts and hold it at 1-2 k rpm. If I let off the gas it will immediately stalls. After it warms-up it runs fine. But I’m driving 2 footed until then. Can anyone tell me where to start to fix the problem?

I’m just guessing, but you MAY have a faulty coolant temp sensor.