Question for you hypermilers. In my continuous attempt to figure out how to get my average mileage above the low-60s, I've noticed that it is nearly impossible to maintain any speed in any gear when the FCD is reading above 90 or so. In other words, if I'm driving 55mph on a flat highway in 5th gear and I put the car into lean burn around 100mpg or so, my speed will inevitably begin to taper off. That of course forces me to re-accelerate back up to cruise speed and repeat the process. If you plotted my speed vs time on any given road trip, it's a continuous roller-coaster of ups and downs trying to maintain speed. Does this seem normal or is there possibly something else to blame (tires not inflated enough, faulty systems, etc)?