Question?
 

What octane fuel does everyone with a stock Mustang or close to stock on this board run in their 4.6 L? I only run Mobil gas, just a personal preference. I've recently switched to 87 octane to see if it will take care of my check engine light. I used to run 87 in my 5.0, and it used to ping, I don't seem to have this pinging problem yet on my 4.6, altough, I'm only on my second tank of 87 since I bought my 2000 GT.

Just curious.

I personally use 91 octane which is the recommended octane for my car. Typically you should use the lowest octane you can get away with, without pinging. Using any higher octane is just wasting money.

i've got a cobra so i run premium. i'm a little doubtful about whether it actually needs to be done. 8.5 : 1 compression shouldn't require 92+. but i'm not going to screw up an aluminum motor to find out.