Does it matter what octane you use when breaking in a new engine? I have always broken my engine running 87 octane, regardless of the mfg. recommendation. The one time I did break my engine in using 93 octane, I found the engine to constantly ping at all speeds when I ran anything other than 93. This was on a vehicle that recommended 87 octane. Once the engine gets a taste of 93, it doesn't like to go back to 87. Does the octane rating at break-in set the expectations of the engine for the rest of its operational life?

 

You should only use the recommended fuel during break in. There is no reason to go with a higher octane, other than making your wallet lighter. If you ping on the recommended fuel, you have deeper issues and they should be covered under warranty.

 

They were never able to identify the issue, the perpetual 'unable to duplicate'

 

That's a bad excuse. Can you take them out for a ride and let them hear it?

Think about it (I am sure you have), why should you have to run premium fuel in a new vehicle that does not require it? Document everything, and keep pushing the issue. That's my vote.

 

Simple solution, I traded it for an '03. Problem solved. But I was frustrated in them giving me the idiot treatment.