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Old 02-03-2006, 10:42 PM   #18
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Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
Originally Posted by Jeph
... The manual notes that the less octane can throw the check engine light...

Sure, makes sense. If the DME cannot adequately compensate for the lower Octane it would cause a MIL.

An Engine may operate fine on the Lower Octane, with the DME compensating for it. But, put the Engine under Load (High Speed, Passing, Going Uphill), or raise the Ambient Temperature (lowering the detonation threshold) and suddenly it cannot cope, which it signals to you in the form of a MIL. I suspect that you'd feel the loss of Performance just as the MIL came on too. Also, an Engine which is Knocking has to cause Havoc with the Emissions Readings from the OČ Sensors too...

Happy Motoring!... Jim'99
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