What octane gas do you use?
 

Just wanted to what octane rating you all use and your opinion on it. I usually run 89 with the occasional tank of 93. And I drive a 2006 4.4i

If I remember correctly, doesn't the owner's manual recommend using at least 91 Premium? Anyway, since day 1, I've always used premium.

Yes it says 91 or higher just much more $$ then 89

Minimum AKI 87 is stated inside the filler cover door.
I constantly fill Esso 89 which is midgrade in Maritimes

Only Sunoco or Shell Premium (Hi test) 93 Octane US

So far I had to fill up the X5 once in the last 30 days as it is sitting quietly under it new Weathertech cover after being washed, clayed, waxed and detailed. Love the new cover!

California Car Cover - California Car Cover Company - Car Cover Materials

so when You ruin your engine don't complain..................wtf

91 Octane or higher. The first time my wife took the X5 for a drive she put 89 Octane and the engine light came on, the X5 drove rough the whole tank!

91 or 93 Octane as available.

Stations I use are Costco, 7-11, Sheetz, Valero. Costco and Valero are top tier gas and workout if on errands that way. 7-11 and Sheetz are close to where I live.

91 as that is the best we can get here in Vegas. If they had 93, I'd run it.

You should take a look at the price of OEM cats for your X5 because a sure way to a premature killing of a cat is wrong octane fuel (lower grade than is recommended). As we say save a little at the pump pay alot in maintenance later.