Paul I apologize to you and everyone who has read my comments on the
use of premium gas. My comment was based on an article I read many
years ago which I have little recollection of except they had run some
tests and proved slight increase of efficiency but substantially
cleaner engine overall. I also have experienced this on my own
vehicle.

I went and did some research on the subject yesterday and have
concluded that the majority of those qualified agree the best thing is
to follow the manufacturers recommendation. Most of these people find
the slight increase of performance if any on today's cars is not worth
the extra cost. apparently the modern fuel injected cars do not gain
performance the way the old carbureted engines did. Also it will
hinder some vehicles depending on their software for ignition
controlled.

On my own truck I get an increase of 3MPG with premium gas and it runs
smoother. As a former Nissan tech I ran into many drivabilty problems
related to ignition systems and often was told by Nissan to instruct
the customer to switch to premium gas. many of these customers I saw
again while in for oil changes and I would ask about the problem
before. All of them replied that the problems went away after
switching to premium. a couple of them said they dropped back to
regular and the problem returned but mid grade solved the issue. As
for clean engines, every once in a while as I was performing a 30,60,
or 90K service I would find the throttle body exceptionally clean. Not
wanting to duplicate a service that a spouse may have already had done
I would go and speak to the customer. Turns out each of these
customers always used premium gas. In my research I found that most
engines designed for 87 octane due benefit from higher octane when
they age due to carbon build up. the carbon build up has always been
my reason for premium. I have seen many engines that used premium and
had very little or no carbon build up even after 200,000 miles. So if
they had no carbon build up why was I working on them. oddly enough
most of these customers wanting to take good care of their engine
failed to include changing the thermostat as a preventative measure,
resulting in a blown head gasket.

Bottom line is: I do not want to mislead anyone as to what grade of
gas to use so I will keep shut about it from now on. what works for me
may in fact not work for the next.

pleas accept my apolagies.

Spat