2001 S60 Rough idle question

[tjmarks]

I have a volvo s60 2.4 non-turbo and have a rough idle issue. My car will start and run fine for the first 15-20 seconds and then start with a rough idle. I get the code P0336 or P0339 but never both at the same time.

Does any one know when the engine starts to use the crankshaft sensor data? My thought is maybe not in those first 15-20 sec. If I turn the car off and back on, it is again smooth for the start and then gets rough. I have replaced the sensor with a new volvo one with no change.

Any help would be great!