This happened to me the other day! First time I've felt something wrong and luckily was close to home so kept the revs low and got it home. OBD11 showed misfire on cylinder 2 so swapped round coil packs on cylinders 2 and 3 and the misfire went away! Drove around, made the engine hot, gave some beans etc. and couldn't make it happen again. Put it down to corrosion on the contact. Cleaned all the contacts with WD40 just to be sure.
Then about 100 miles later it happened again. Unplugged the coil packs on the side of the road and plugged back in and it went away again for another 100 miles or so again. This time OBD11 showed the misfire was cylinder 3, so seems that coil pack is on its way out.
Looking at them they are all different versions of Delphi coil packs so I think they've been replaced one by one over the years. I'll replace all 4 and hopefully fix the problem.
