I've been gettin a lot of misfire i have a volvo s80 2.9 engine non turbo 1999... cylinder 1,2and 3 spark plugs were all full with combustion. i replaced them with new ones and also switch the coil pack to cylinder 4,5,and 6. within 30 min the same thing happened on the same side. so i know the coil packs are working. what can my problem be. the obII gives me the code of p0134, p0300 and p1174.