All,
My wife's ​2011 LR2 has about 95k miles and has had a steady diet premium fuel it's whole life. Yesterday I filled it up from near empty with 91 octane "non-oxygenated" fuel instead of the 92 octane with 10% Ethanol I usually use. It was the only premium available at Kwik Trip, a major gas station chain in the upper Midwest. Always tighten the cap down to like 8 clicks.

Within a few miles it was idling rough, then stalled at a stoplight. Once restarted which took a longer than normal crank, the CEL came on and has been on since. Rough Idle has smoothed out and it only stalled once. Drove it last night and it seems to run just fine.

My theory is that between the lack of Ethanol, warmer weather and switch to "summer" gas by the refineries, it went briefly out of tolerance and threw the code, but has now sorted out the various ratios and is fine now.

​​​​​​Any thoughts? Thanks!

 

Sounds more like the gas was contaminated or perhaps because the tank was near empty, filling it back up stirred up some sediment that got pumped into the fuel system and possibly clogged some injectors temporarily... just thinking out loud.

 

Did you over fill the tank?

Over filling can cause rough running