I have a 2004 merc sable gs. It won't stay running when cold. has engine code 1633. Do you know what this is?

Look at the automatic Idle control module first then the engine control module.

The idle air control valve is designed to adjust for the load on the engine to maintain the idle quality. When it's cold out, it's more important that the engine temperature sensor is working correctly so that it can trim the fuel richer to compensate for the cold running conditions. Also, a dirty Mass Air Flow sensor could give you problems with your idle. A shop could easily diagnose the poor idle quality for a reasonable fee if you don't feel like throwing parts at it again. Have you experienced unusually poor fuel economy or better than normal fuel economy this winter?

Could be a weak thermostat thats not closing when the engine is cold.

Try disconnecting battery negitive battery terminal for 1min 30secs with ignition in the on position.If this fails to work a code reader is required to reset computer.... hope this helps!!

I suggest scanned the ABS module in order to know fault codes stored there. Just with this code number could send you solution details. Could be a probem with the sheel speed sensor misadjust, but will need confitm with the codes finded.

take it to the dealer and have a cert Ford / Merc shop program the comp, they can reboot and install what your car calls for ,

Ey sounds like you have a bad alternator so you should test to see if the alternator is still good or bad by let the engine running then pop the hood opened and disconnected the ground cable off from the battery terminal so when you do that and if the engine dies then you have bad alternator but if the engine still running after disconnect then your alternator is still good

...are under hood, a diagram on top of radiator support.

I have this same exact problem in my 2004 Mercury Sable. It seems that it causes scrapping noise in my engine though aswell. I have had it for a few months and I fix it but turning the car off after a minute or two and just restarting it. That seems to fix it but it's progressivly gotten worse.