My check engine light came on about a month ago. I had it checked out and the error message was misfire cylinder 3. I did the full tune up. Nothing! the car runs rougher now. I put the car back on the OBD machine and now I get random misfire P0** message. I read something about coils. What are they and where are they? Could that be the issue? The car putters when it hits about 80/km then smooths out when you hit around 100/km. There is no kick to it and it shakes when I come to a stop. Any help on this would be greatly appreciated

 

maybe it,s time to replace all the coils,it can a source of Misfire.

 

the 98 S70 doesn't use individual coils. It has a distributor and a single ignition coil. As for the misfire problem, especially since it's a random miss, I'd start looking at the fuel system. Clogged fuel filter or a little water in the tank will cause this. A bad Camshaft position sensor or a dirty/ damaged MAF is another common cause. A weak ignition coil is another (unlikely) possibility.