Hi. In the IPD catalogue rankings, I am closer to Skill Level 1 than 2. But I learn so much from Brickboard and appreciate the advice, and the unravelling of many things mysterious car-wise. It's like having an unlimited supply of brothers and dads out there to turn to (and some savvy sisters, too). I feel more confident of the tires I choose, the references I use, and the questions I ask mechanics. So, before I see those mechanics again this week, I wanted to run the latest by you all. I wrote Friday night about some disconcerting bucking I was experiencing near the end of my three hour drive out of state. The next morning I isolated the motion to occurring randomly at speeds of 40 mph and faster. The local mechanic suspected a shift sensor problem, and I made it home traveling the turnpike by switching on overdrive (orange arrow) every time the car started to rock. After moments of steady driving with the orange arrow on, I would switch it off and sometimes be pleased to find the car sailing normally. However, this serenity was short lived, and the whole drive was defined by this back and forth, as if the transmission couldn't decide where to settle. "Rock the Boat" came on the radio during one of these spasms and I noticed my car keeping the exact rhythm, feeling very much like a rocking boat, baby. The only predictable way to stop it was by turning on the orange arrow, and the only predictable condition for setting it off was when driving downhill (arrow off)-- the minute I let up on the gas to slow the speed, the dance began again. Fuse #11 (fourth gear)looks okay. Guessing the next checks are the overdrive relay, then od solenoid? But I wonder, are these "back and forth" symptoms of something on the blink but not yet dead? Something loose? Possibly something easy? Any insight is appreciated, as always. Thanks. :-)