Didn't know where to post so here it is again..

[Iliveforum]

Hey guys so two days ago my Mazda 6 was running GREAT, drove it to northglenn from Denver and back, and ft Collins and back to Denver the day before. It was running flawlessly. So after the trip to northglenn and back, my girl drops me off at work and heads to run errands in englewood. I get the dreaded phone call at work 20 minutes later that the car started shaking uncontrolably. Tought it was the tranny by her description. So I go back out to englewood after work and drive it around, not a single issue, she said the check engine light came on before she shut it down, no light, no shaking. So at that point i drove it back to my place in the city, sure enough after 20 minutes of driving (and making the last turn onto my street) the car starts to shake and the check engine light starts to flash. A sure sign of a misfire from what I've read. The shaking happens at low rpm at crusing speed it's not as noticeable, in park it's hardly there but in drive with the e brake on it's there. SO what I'm looking for is confermation that it is a misfire.
A few side notes, this literally happened at 100,000 on the dot, I JUST bought this car 2 weeks ago and I drive ALOT, a thousand miles in two weeks. Changed the oil and had the fluids checked 2 days before this happened as well, the day it happened we switched from regular grade to mid grade gas. I'm running full synthetic oil in the car. it's an automatic 05 Mazda 6s GT wagon and the motor and car is "unmolested" says the Mazda dealer at gateway Mazda so I'm assuming this is an issue based on it having high milage/a fluke. One last thing, almost as soon as this issue started the tranny started to intermittently become rough on down shifts in random gears, most notably between 3rd and second and 5th and 4th. It's far more rare in sport mode but it is vastly rougher then it was a week ago or even the day before the engine issues. I NEED ADVICE QUICKLY!!!

Thanks
Keegan