Indeed. the price of gas is soaring.
I have a 1993 190 E. 4 cylinder/5 speed. Been using supreme unleaded (91)
for 3 years (since purchased).
Due to price spikes, I consider using 89 octane. or a blend or 91/89.
What's the effect of a lower octane rating for a few months....
I drive 200 miles a day r/t..

Let me know, please...

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THANK YOU. CONRAD

Have a look at these discussions:
http://www.peachparts.com/shopforum/search.php?searchid=445799
Take an aspirin & call back in 2 weeks.

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2007 C 230 Sport.

just use what the manual says. you might not hear detonation but it does occur. also you might not get as much mpg as with the super so it could be a false savings. also mercedes has no system that adjust timing for the fuel you use. some will change the timing if it detonates but this is not to be confused with changing timing for the gas. you do not want your car to detonate.
its a hint that bad things are happening.

george