I have a 1988 260e, it runs fine until it get to operating temp, then it starts misfiring. It gets so bad its almost not driveable, once it sits and cools off for a while, it runs fine again for a couple of minutes until it warms up. I had a mechanic put it on a scope, and the spark was fine, he said that my fuel dist may be out of adjustment, but couldn't really figure it out. Any thoughts or suggestions would be appreciated. Thanks!