I was just reading the octane posts. The guy who sold me the car told me to put 89 octane gas in it. I only have 1200 miles on the car but it has all been with 89 octane. Did I do any harm during the break-in period?

07 Stock GT

 

no.....

 

not at all, in fact, if you go even higher you might get a bit more pep out of the car as the timing adjusts to a slower burning fuel.

 

what about now going back to 87?

 

No worries at all. The OBC will adjust to pretty much whatever you put in it between 87 & 95 although I understand from a tuner that they are happiest with 91 or 93

 

There is no reason too.....