Cheap petrol, change stations, to much ethonal content.

 

If your engine is really getting hot it can start rough when hot turns out to be first signs of a restricted radiator. Believe it or not then your temp gauge will start to creep and overheat eventually.

 

Thanks for all the posts, I think I found the problem. A while back I had a problem with a really high idle 2000-3000, for which I brought it to the dealership to reset the base idle. They did the ECU reset and gave it back and it ran fine (I thought). In trying to fix this latest issue, I noticed that the base idle screw cover was missing and decided to to see if backing the screw out a bit would help..... I found that the screw had been turned in all the way. I have since backed it out (trial and error) to a point where the engine never stalls and it holds idle at about 650-700 rpms. I have a feeling that they closed it to decrease the idle and then reset the ecu. The times when the engine needed to let more air in for idle, the stepper motor could not open far enough to let enough in and the car would sputter and stall. Since I adjusted the screw, I haven't had it die out once..... anyone else think that this is plausible?

 

That sounds totally plausible.
Thank you for posting the fix.