The team discovered the fuel when the No. 24 Chevy was being topped off after Gordon had made a few short runs early in practice. Once the team found that the fuel was clear instead of blue-ish green tint, the crew alerted officials to the problem.
At that time, they pumped the fuel out of the car and NASCAR officials took a sample for analysis. NASCAR also checked all other teams to see if they had the same problem. No other issues were found.
Track gas tanks contain lower-octane fuel that can be used to fuel track vehicles. Sunoco officials take control of the pumps the day before the track opens to ensure that lower-octane fuel doesn’t find its way into the race cars.
Teams are given gas during inspection prior to practice, and only after the fuel cells have been inspected.
According to Mike Mulhern of MikeMulhern.net:
A look at the three fuels available at the garage gas station shows two leaded fuels, one 114 octane, one 116 octane, and a third labeled ‘unleaded’ read “GTX260” at 98 octane. NASCAR teams are to be using the unleaded fuel. It would appear — and this is what some rivals were told — that a gas pumper inadvertently put some of the ‘leaded’ fuel in Gordon’s car.
That has yet to be confirmed.