[ShadowReaper]

The only thread I found useful to help me understand Fuel Trims, the OP had 100 Octane.

I moved from Florida where they have 93 Octane, to Colorado where 91 is the highest. I'm JDL Turbo'd tuned. To make this clear, I have NOT been getting insane Fuel Trim reads like (-28 or +30). However, the trims seem to love being in the Negatives. It does not look normal to me.

Keep in mind that I noticed this issue couple days after I got a revision from my tuner (due to the move) I went for a test drive to see what my Fuel Trims looked like.

On Idle

ST: Lowest: -4.7 Highest: 0.8

LT: Lowest: -4.7 Highest: -1.6

On normal driving:

ST: Lowest: -11.7 Highest: 2.3

LT: Lowest: -3.6 Highest: 0.8

Again my point is that I am heavily on the negative side. I was on 91 octane for around a week before the revision and I didn't see readings like this, this is why I don't think it was just the switch to 91 form 93.