Stilo Change your spark plugs!

It's pretty much in reverse now. Refit the coil, and re-attach the ignition lead. Push the plug home, then press the yellow clip in. If you've got more plugs to do then crack on, if not then re-connect the battery and start her up. Listen for a different engine sound and throttle response. If you think something's wrong then with the engine running, carefully remove the igntion leads one at a time listening for a difference in engine note. If you pull one off and there's no difference then that's your problem pot. If you have a Sagem coil, proceed to your nearest Fiat parts desk, beat manager about head with faulty coil, and purchase a new one, and fit as per re-fitting following a plug change.