[JimD]

Dack (or anybody),

Your story is somewhat like mine, at much slower speed in my case, except my result was different and I used lower octane on purpose. I tried it, my engine seemed to like it OK, so I kept using it. I wonder what you would have done if it seemed to perform the same on 95 octane.

This is off topic but relative to cleaning the intake on a n54 or n55, has anybody reported trying Seafoam? It can be added to the gas, added to the oil, or added with the air - squirted into the intake. For this I think you would want to squirt it into the intake. Project Farm is one youtube channel that tried it in some old engines - much less sophisticated engines - with good results. It seems to be fairly effective in removing carbon deposits. Our cars, even mine, are pretty expensive to try things like this with but it might have benefits something like walnut shell blasting.

I kind of think BMW motors are cry babies. When mine needed an alternator, it started showing me the battery symbol incessantly. My battery is 9+ years old so I planned to stop and get one on the way home from work. On all my previous cars, they would run at least 50 miles on a battery - it doesn't take that much to run a car. It takes a lot to start it but I am carrying my jumper cables now because my battery is so old. When I went 10 miles or so with the battery symbol on, the car started mis-firing, the wipers came on, and everything on the dash lit up. I stopped and called AAA who measured the battery voltage at 11.6V. That is a little low but does it really cause a mis-fire? It would not on my older cars. They would just crank slow or refuse to crank. I know we have a lot of electronics and really need the electricity to work properly but I think BMW in their corporate wisdom has programmed our cars to throw a fit when things aren't going well to be sure we notice. Just my theory. But I know what a mis-fire feels like.

Jim