Friends,
I'm currently working on my Daughter's 2007 S60. the car has 150,000 miles on the clock, and its been well cared for. On the way back home this past Monday evening, she told be the car began to mis-fire and shudder violently while going up a very long hill, to the point that the car threw a code and had to be towed back home. After getting her back home, I read the codes and it claimed a misfire on coil pack 3, but also had catalytic converter damage to boot! I immediately changed the plugs(all looked good) and ordered 5 new coil packs.I did the extended test drive after the plugs and coil-packs only to have the car exhibit the same shuddering that she described before this recent work. Car runs great on the flat, but exhibits this shuddering while going up a long grade, then straightens out immediately after. (no new codes after the plugs/coils, just the shuddering).
Could I have a plugged catalytic converter?