My Transmission & Auto Care Experts is occasionally asked by our customers in the greater Houston area about what octane ratings in gasoline mean. My Transmission & Auto Care Experts tells them that the octane rating in gasoline is a measure by which that gasoline is capable of helping to prevent engine knock, also known as rattling or a pinging noise resulting from the premature ignition of the compressed air-fuel mixture in one or more of an engine's cylinders. The majority of gas stations around the greater Houston area sell three grades of octane, 87 octane (regular), 89 octane (mid-grade), and 92 or 93 octane (premium). Octane ratings are located on each gas pump, usually as a bright yellow sticker. If you live in the Houston area and have any other questions about the fuel you use in your vehicle please feel free to contact My Transmission & Auto Care Experts and let one of our auto repair mechanics be of help!