I was telling another Ranger owner that mine knocks going up hills & gets 19-21 mpg. He said there was a recall for bad coil packs on the 1999/2000 models & when his coil packs were replaced the knocking stopped & his mileage went up to 22-23. Sounded far-fetched but I thought I'd ask if that's a possibility in my case. Mine's a 2000 with 3.0, automatic & 69K miles. After I got it last summer I ran Seafoam through the vacuum hose & drove it around. Twice. Then changed the spark plugs & wires. Still knocks with the cruise control at 60-70 going up slight inclines, even in winter. It's always had a slighly lumpy idle when warm too, like a sporadic misfire. Anyone heard of the coil pack being the problem? Thanks for any replies.