Nissan Repair: Engine stalls after 3-4 min at idle on cold, throttle position sensor, variable resistor

Question
The engine is cd20t on Primera 2.0 TD SLX (1998). It starts without problem and works fine for 3-4 min.. after that it stops (it happens on winter conditions). I can start it again without problem... When engine is wormed up, there are no problems.
I have bought this car recently, and I replaced engine oil, oil filter, air filter and fuel filter with new ones. I should mention that on cold there is a squek noise, (something with drive belts). Also, on cold idle, when back windscreen heater is turned on (or some other electric consumer), the engine noise becomes rough. The malfunction indicator doesn't indicate any problem.
Thanks in advance

Answer
Zoran,

The idle problem is related to the transition from cold to normal operating temperature.  I would check the throttle position sensor to make sure that it is adjusted properly.  You will need a volt/ohm meter and it is just a matter of checking the voltage for idle.  This is more of a positional sensor and not totally a variable resistor.  So, when the car is at idle the computer reads this from the sensor.  I do not have the resistance value for the idle on your Primera.  I hope you have a manual.  

Another cause for the idle problem and the stall when cold is the temperature sensor that tells the engine that it is cold is allowing the engine to get out of choke mode before the engine is actually warm.  Is the temperature showing normal operating temperature when the car is warm?  If the engine is running colder than normal the car will stall when it transitions from cold start mode to normal operating temperature.  A new thermostat would be in order if that was the case.

The belt squeal is from the belts being old or loose.  You need a half inch of play when the belts are tight and new.  Any more than this and you damage the bearings on the accessories.  

When the engine is loaded with additional electrical demand the engine runs rougher than normal.  Have the spark plugs been changed?  If not change them and you could solve both the cold stall problem and the rough idle.  Basically, you have a four cylinder and the engine is loaded to the point it runs rough as all in-line engines run rougher than "V" type engines.  Being a 98 model does your car have a cap and rotor?  If it is so equipt I would replace them along with the spark plugs.  Do not use Bosch plugs as I have had trouble with them in Nissan cars.  The work great at first and then the car runs rough.  I would use Autolite, NGK or the like.