My 99 V70 non-turbo just started this issue. It idles rough but when I accel it runs smooth. I also put the pedal to the floor and it take forever to get to 60. The ets light is on and has been for a while but always ran perfect. My codes that I pull is p1017,1021,1026,1027,1031. Before it started running like this I had a o2 sensor fail but I replaced it. The odd part about this is that after sitting 2 days it ran perfect for a about 40 miles. Then when I started it up it did it again. I have checked for vacuum leaks but it fine. I changed all the plugs and checked the coils but all spec'd out.