[101Volts]

Night_Sailor, Have you tried anything else Opti-Lube sells such as their "Boost!" formula which increases cetane by 7-9 points instead of XPD which raises it by 3 points? I don't know if "Boost!" will increase MPG more than XPD or not. I have a bottle of "Boost!" and haven't used it yet. Nobody else I've seen online outside Amazon reviews has used it.

EDIT: I've been using Opti-Lube's "Boost!" and "XL" (the latter's a lubricity improver) simultaneously.

Boost: 1 oz/10 gallons
XL: 2 Oz/10 gallons (slightly lower than the recommended maximum treat rate of 2.5 oz /10 gallons, or 5 oz/20 gallons.)

I have noticed a small increase in engine power with this mix, but it's not much. It's enough to prevent as much downshifting up hills when the torque converter's locked, which does help.