Having fun and games with my high mileage 2001 XC70. I have had low, slightly rough idle issues for a long while, and had planned a ETM change on advice from 'experts'. On the way in to town, I lost all oil when the camshaft seal blew out. Stopped and the refilled oil, then managed to get it the mechanics before the oil light came back on, and the temp never got above normal. After the oil seal repair, the idle was really poor, so the mechanic replaced a coil pack, which improved the idle to where it was originally. Wife was driving it a week later and the car shit itself. Rough running and flashing CEL. At home, I got misfire code p0300 and I found the top of the engine was flooded with oil, and the oil level was way too high. I drained out 1/2 liter of oil to correct the level, and wiped up the mess. I then replaced all plugs with new NGK Iridiums. The idle was still crap so I tried individually disconnecting plugs to the coil packs. This didn't make much difference on one. I then looked for spark, and found that the coil would not spark regardless of the position it was tried in, and when placing other coil packs in the originally bad position they worked. I also found a pushed in pin on a another packs connector which could have caused my original idle problem? I confidently ordered in a new coil pack, fitted it, and still got a bad idle (#$%^&). I went looking for spark again, and found a previously not checked (#4 under the air pipe) coil pack to be dead. I swapped coils extensively to once again prove the coil pack dead. Now I'm looking at spending more money to replace a 3rd coil pack ($170 a pop in Oz). I can't see a smarter thing to do? But part of me feels worried that I'm chasing shadows. Anyone see a hole in my technique, or had similar experience? My theory is that the potential overheat from the camshaft seal failure, or the hot oil soak from the overfill caused the coils to fail. Hopefully I am one coil replacement away from success....