bad gas twice??

[Wwwdrw@xxxxxxx]

bought 328i w/ 10k.  unknowingly ran on 87 oct gas for 47k.  Two weeks ago I 
filled  up on 87 oct at a questionable gas station.  Next morning, car would 
start, but stall everytime I tried to put in drive.  Finally got it in gear, 
ran down gas 1/4 tank, filled with 93 oct, ran out tank, been filling with 93 
oct since.  I thought bad gas was the reason until this week, on a full tank, 
the same thing has happened again.  Could this possible be bad gas again in 2 
week????  I have 58k.  Car is running great now.  Help please.

------------------------------