You might want to check your fuel filter. Your car requires more gas when it is cold. Just a thought. Let me know what you find.

 

so it does it cold, and then after warm when youre wide open, right?

i think u'll probly have to take it somewhere to confirm, but it makes me suspect a missfire. if its definately just a vibration and not engine performance related, disregard this post. so anyway i worked on a older body style MC a few years ago that ran rough when it was cold and the customer said it also did when he drove it hard at times but i couldnt reproduce the second part.

ended up just having to clean the injectors. btw i've never personally seen anything but GM's 'top engine clean' fix a check engine light by cleaning injectors.

 

I've been meaning to change the fuel filter and get an oilchange/lube this week so I made appt with dealer to have both done on Friday morning... will post back with result.

 

So far, pretty much yes.