At the time of the failure, the fuel filter had been replaced about 5000 miles previously. I changed the fuel filter every 15K miles, always with an OEM filter from a GM dealer. After the first failure, I changed the fuel filter again, but the problem continued. This first happened on July 26, about 60 miles after refueling (41 gallons) at a Pilot/Flying J in Columbus, MT. So, would bad fuel have an impact that quickly? Probably no way I could substantiate bad fuel at this point. Thanks for the feedback.