try another dealer. works for me on a 99 ranger with a cold knock. ac collins ford had the truck for 5 different tries and told me it was carbon knock. they removed the head and scraped the pistons and valves and said that it was fixed. not!!!!! i finally took it to charle thomas ford and of cource, they heard the knock and ordered me a new engine to be installed this week. just do not take no for an answer.
