Hey guys,

i have a 2009 flying spur (NOT the speed ed) and am experiencing rough (almost stalling) idle upon startup. It happens both when engine is cold and hot. If I keep driving, the sputtering does not stop and the car makes sounds as if it's angry. Strange thing is, if I turn the car off and restart, the car is perfect. This has been happening for 3 days and happens every time I start. What do you think the issue could be?

I had had the infamous vacuum hose replaced a year ago, a recent oil change and clean bill of health from Bentley a few months ago. and there aren't any check engine lights or warnings on the dash. I DID however, about a week ago, find myself low (1/4th of a tank) on gas on the way to work. I pulled into a shell station to find that they only had 87 octane (I usually put in 93). Knowing I had 1/4 of a tank of 93 already in the tank, I put in 3 gallons of 87. That got me to half of a tank of what I thought would be a 50/50 mix equivalent of 90 octane. Reasonable? On my way home from work that day, I filled the remaining 1/2 tank with 93.

Could this be causing my issues? Could the 10 mile trip I drove to work with half my gas being 87 octane cause these symptoms?

Thanks for any input!