Back in 1995, Acura eliminated the Vigor and replaced it with the TL. The TL had a nice run, lasting all the way through the 2014 model year, but the TLX is set to replace it in 2015. The 2005 TL and its 270-horsepower, 3.2-liter V-6 had rather specific fuel requirements.
Oftentimes, manufacturers recommend using premium fuel, but regular fuel is perfectly acceptable. In the case of the 2005 Acura TL, the manufacturer stated that premium fuel with an octane rating of at least 91 is a requirement, and the use of anything lower than that may result in engine knock or internal engine damage. Acura did state that it was okay to use a regular fuel above 86 octane if 91 octane was not available, but only temporarily.
