My 2008 Taurus with 65K miles has developed an odd hesitation. It usually occurs at highway speed (around 70 mph), under light acceleration (1500 rpm) and usually when going uphill. It will appear at other times, but that scenario is the most predictable. I have also tried to see if the condition would worsen under hard acceleration at highway speeds, but have no problems. I have cleaned the mass air flow sensor with no improvement. I also do not have any check engine lights, and the Autozone scan showed no codes. Has anybody dealt with this situation?