That addresses point #3 of my post above, Paul (I think this article was in Car & Driver - I had seen it too). What about the other three points (1, 2, and 4) - are they fallacious too, or is there some truth to them, especially in the context of 15yr+ old cars.

Some people recommend using premium fuel before an emissions check, as it gives lower HC readings. That got me thinking on the cat convertor issue for old cars - after 15 years, the cat has got to be partially plugged - wouldn't premium fuel extend its life? Again, I am just raising these issues, I do not have the answers, obviously.

thanks.

Personally I use premium in any car I drive.

The cars just run better on premium.

Personally, I get the following from using premium...

Better gas mileage, lower emmissions, easier starting, more power, and a cleaner running car.

For me the price difference is negligable, but then again, I don't have to pay for my gas, so I will use the best there is.

My car was designed for premium, so I use it. plain and simple.

I tried 89 once, and the car ran horribly.

Alon

__________________
'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon

RE: Cleaning ability of premium fuels vs. "regular"

Obviously, the answer to this question depends on the additives each company includes in their fuels, but I believe the increasing popularity of fuel injection (and finicky fuel injectors) over the last 25 years has narrowed, if not eliminated, the gap in the cleaning ability of premium-priced fuels over "regular".

Even if a given premium fuel had markedly better detergent qualities than regular fuel, the usual cost difference would be substantial enough to make this an expensive way to keep your combustion chambers clean. Instead of burning premium fuel for this purpose, stick with regular and buy a bottle of Techron (Chevron) every few months.

My daily driver has a Ford 4.6 V8. Manufacturer's recommendation is 87, I use 89, particularly in Summer, and pretend I can feel the difference.