how many miles are on your car?
When was the last time you replaced the spark plugs, spark plug wires and ran a bottle of fuel injector cleaner with a tank of gas?
If your car has over 75,000 miles on it and the serpentine belt that runs the engine accessories has never been changed, it should be.
Worn spark plugs with a larger gap require a higher voltage to build up before the spark jumps the gap and becasue a higher voltage needs to be achieved the resulting spark is not as hot. Degraded spark plug wires will have a similar effect.
Lower spark temperature will cause a notable change in the ability to initiate the fuel burn especailly when there is a rapid change in manifold pressure like when you step on the gas a little as you let the clutch out. Cold wether only aggrivates the problem.
Worn serpentine belt can allow the altenator pulley to slip slightly, just enough that it turns slower than the engine but not so slow that it squeels. This ammount slower is just enough that the altenator can't make the power it needs to when the engine is idling. Also if the belt is worn, cold weather will only make allow the belt to slip all the more before it starts to squeel.
If your car has over 70,000 miles it is not unresonable to suspect the altenator is nearing the end of its life and is getting tired and sometimes doesn't make full power.
