2000 ford explorer xls, awd, 4.0 ohv, with the five speed automatic. tranny shifts fine, but sometimes while cruising down the highway, I'll press the accelerator to pass somebody, and it feels like the tranny gets confused. (should I kick down? Should I unlock my torque converter?) I'll have a serious drop in power, accelerate slowly, and the thing shakes like I'm going 70 MPH on railroad tracks. And I don't mean on the rails. the truck has 74K miles, fluid looks good, replaced plugs/wires, and the problem is intermittent. Anyone else have this problem, and what do I look at to fix it? I've heard everything from changing fluid, changing spark plug wires, etc. Help.