My 98 GS something in the morning when i start it up it won't hold idle...rpm would go up and if i don't get it a little gas, it would drop right back down. That only happen when the car have been setting for a few day without driving....anyone know what going on here? I have change the spark plug, filter, oil change, etc.

 

good post. my old car used to do that too. bump

 

my car did that once. it was -16 celcius outside.

 

Two things to check would be:
1. A/C signal circuit (Compressor circuit)
2. Fuel pump control circuit