Do you get the ETS light (this is the ECM)? If you don't get that it probably isn't the problem. CEL light common fault, I read, is a bad fuel cap. giving random signals due to a bad seal. You've not mentioned a bad injector as a possibility for your misfire problem. See if you can run a Vida scan when the CEL light is on. CEL light reset is easy on this model, no tool needed.
My 2000 V70XT (P1/P80) had ETS problems and I converted it to full electronic with a Sacar module. Not expensive, £75 on UK eBay, and not difficult to do if you are handy and follow the instructions to the letter. See RobertDIY on YouTube. Unless you are that man in which case I'm not probably going to be helping you much!!! I also had a bad vacuum leak from one of the small tubes that goes to the front right of the intake manifold. That helped with my tick over as the computer was trying to correct for a weak mixture and making it too rich.