Originally Posted by BetaDnB
I don't see how an ECU flash would do that. It sounds more like your wheels are slightly out of balance.
Yeah, I thought the same so I bought some brand new tires and got a full re-allignment. Still have the same problem. The shake becomes most violent when driving up hills between 65-75 mph. It's almost like the car is struggling. I attribute it to the ECU flash, since perhaps they changed way the air/fuel ratio.
Who knows though, it could be anything. I'm off warranty now and ford charged me $175 to diagnose and didn't find anything wrong.