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If the vehicle has the 6.2L V8 engine (VIN Code W), use
premium unleaded gasoline with a posted octane rating
of 91 or higher.
If the vehicle has the 6.2L V8 engine (VIN Code T)
or the 7.0L V8 engine (VIN Code E), use premium
unleaded gasoline with a posted octane rating of 91
or higher.
If heavy knocking is heard when
using gasoline rated at 91 octane or higher, the engine
needs service.
Last edited by Vette_DD; Mar 23, 2017 at 04:41 PM.
Modern cars will just pull timing if they detect knock from lower grade gas. Heck, they probably have separate fuel tables for 87, the ls2 did so I can't imagine the ls3 doesn't.
The one thing you have working for you, is that 91 octane is a minimum of 91 octane, which is randomly tested by weights and measures to be accurate.
Most fuel stations have 2 tanks. One holds 87 octane fuel (as low as 85 in the rockies) and the high octane tank holds 93/94 depending on where you are.
What's this mean for the consumer buying 89, 90, 91, and 92 octane fuel at the pump? It means that the higher octane requirement you call for when making your selection, the more of the higher octane fuel you get. In reality, machines are good but nothing is 100% accurate. You could be getting 92