Vibration while accelerating between 30-40 mph
 

Looking for any suggestion on a problem with my 05 Ford Escape Hybrid. Vehicle runs fine but if I am maintaining a speed between 30-40 mph or accelerating between that range I get a really bad vibration. I also get a strange vibration when accelerating through corners. The vibration goes away if I let off the gas, but returns if I accelerate again and still going within that speed range. Thats the reason its so confusing is because a bad tire, or weights being off would continue to vibrate even if I let off the gas. Any suggestions would be greatly appreciated, thanks.

Have you tuned it up? It is possible the engine misfire is only noticeable under a certain speed/load range. A scanner that can read Mode$06 data can pinpoint if a cylinder has misfired.