Took our caravan away for the weekend, didn't make it, engine started misfire after 30 mins in traffic queue so I stopped and reconnected the electric fan (installed 1 year ago but never used) misfire and power loss continues for another 15 minutes then came that hill. Gave up when the temperature gauge suddenly went from normal to overheat zone. Got towed back home and restarted no misfire, next morning took on test run for 5 miles OK. So we hooked up the caravan again but after 2 miles could hear and feel that misfire creeping back.