First of all I want to say a huge thank you to everyone that replied.
Second the car has been properly maintained according to the matience guide. It use to be my grandmothers car, and she assures me that she's taken it in. ;> (I'll check on the fuel filter)
Third the car is a 1998 Mercury Mystique GS model 2L with only 21,000 miles on it. I'm sorry for not posting this information in the first place, this problem is getting irratating, and it was the last thing I was thinking about.
Fourth, I trust this mechanic and yes he is certified. I have three other people in the family that take their cars to him, and he comes on high recommendation from a family friend. (I trust him far more than the dealership that I was taking it to for warranty work.) His work on all other occasions has been exemplary.
HITMANinMI thank you for the information you gave, it's a big step in answering this. My problem sounds exactly like yours. It's not so much that the light come on while/during the 70+mph it's a more of a common thread of the days that the light has come on and what I've been doing behind the wheel. The days it has come on are just after I have been excellerating to those speeds, days that I have not (staying around 50 or so) the light stays off.
And to GregH yes that is more than I wanted to know, but too much knowledge is never a bad thing when it comes to dealing with mechanics, or anything else.
Thanks,
Ink
