Go to home page and then to 94 to 99 section and then tech discussion. You may even do a search and see someone who has experienced the same problem and they have a write up of what they did to fix. There should be a button on the dash to turn it on. They also had problems with the electrical connection at the window getting cruddy and breaking. Good luck. Why the heads for the miss? Bad valves or something? Lots of things cause a misfire but if new heads and new other parts while in there fixed it then great. Always pay attention to the check engine light and always get the code and post here for help. Here meaning in the tech area for 94-99.