just wondering since I think it may have happened to my old one, previous owner had car for 100k as his exact words were "never felt a need to put premium in er even though it says it needs it, just a marketing gimmic from gm"



does this lead to premature failure of any parts or just degraded performance?

its says in the owners manual Premium is recommended but not necessary, but dont expect to have the power that the premium provides

85 would creat pre detonation and ping. not a good thing..87 is far to low usually.

yes it would...

The 95 manual says you can... but 85 octane? Where do you get a rating that low? Lowest around here is 87.

My manual says to use 91 or high only. They say it may be O.K. to use 87 in an emergency, but if any damages occur it will not be covored by the warrenty.

I've seen 85 down near St. Louis. Never seen it up here in Iowa, but I know it'* out there.

I see it in Michigan all over the place... I haven't seen it in IL yet but really haven't looked. IIRC 85 is some what new, you see that Ford is big on their new trucks/cars being 85 safe. It is mostly ethonal based and ment more for fleet cars etc. that do a lot of highway miles. It is kinda a joke just because yes it is cheaper but you will get worse mileage with it. How bad who knows - I haven't been $$ broke enough to try it. The difference in price is not worth it to me...

Whoa, hold on there Blazin! We're talking about 85 octane gasoline, not to be confused with E85 Ethanol blend. The new cars from Ford to which you were referring are called flex fuel vehicles, and can run on regular pump gas or any Ethanol blend up to 85%. E85 and 85 octane gasoline are two completely different things. A stock L36 Bonneville could run on 85 octane, but NOT on E85. There were no flex fuel Bonnevilles manufactured. According to an E85 website, the 85% Ethanol blend is actually 105 octane but contains too much alcohol to be used in a vehicle that is not designated as flex fuel. Hence, when you see a Ford Taurus drive by that has an "FFV" decal on the rear decklid, it indicates flex fuel capability.

More info here:
http://www.e85fuel.com/index.php

Again I repeat, DO NOT put E85 in your Bonneville! Your PCM, injectors, and fuel lines were not engineered to operate on a high alcohol fuel!