Car: 99 s70 turbo awd.

Ok so this started about a month ago very small. At lights it would jump RPM's once in a while, now it does it a lot more, sypmtoms:

1. does not do it much when the engine is cold.
2. when the car gets warmer its almost all the time.
3. sputters/ missfires under acceleration or at a red light or in park.
4. does not sputter under cruising conditions.
5. CEL is on and will blink if I accelerate to hard and i can feel it missfire
6. Service engine light comes on when the car starts then goes away about 30 seconds into driving.
7. The problem has been getting worse and worse over the past month.

Thanks all in advance hope I explained my problem clearly, I am thinking its a coil pack but not sure.

 

Have you had the codes read? It is a free service at most auto parts stores in USA.