You had to give that booster a chance to mix with the gas. Diffusion is pretty slow.

Glad you're making quick headway with the problem. I would recommend 91 or 93 on your next fill up, then back down to 89 for a couple of tanks to see if the knock resurfaces.

 

Still on the tank of 87 with Lucas additive as I mainly do shorter in town trips.

Last week I thought I could still hear something with an immediate restart although very subtle.

This week the sound is gone after an immediate restart. This isn't the fix I was anticipating as I was fearful of something expensive however I'm pleasantly surprised.

I'll use 91 next tank and hope the power is the same. With this additive, even using 87 base, there's quite a bit more pep.

-Eric

 

Been a few months and I switch back and forth between 89 and 91 every tank (only use BP) and the sound completely vanished while using the octane boost and never returned.

-Eric

 

Update:

It's been 5 months since I first heard this noise and after initially running the octane boost then switching to mostly 91 octane (few fills with 89) the noise has never returned. Might be unique to my car (miles, condition of other components, area (pressure), outside temp, etc.) but I can safely say low octane was the root of the problem. I won't be going back to 87, however it is possible that I had a tank of bad gasoline.

-Eric

 

Seems to have reappeared periodically. I moved to the West Des Moines area and BP is hard to find her and when I do it's $0.20 - $0.30 more than other fuels. Unfortunately, "other" is Kum & Go and I wonder if their 91 octane isn't the same quality as BP or others - I have been running Sam's Club 91 octane for a month or so.

There's now another thread with a similar situation and the dealer blamed it on "winter gas". My first occurrence was February 2018 so similar time of year.

Other thread.

-Eric