I finally tried it at 2oz per 10 gal. of gas in my 94 4.0L Ford Explorer. Within 10 minutes of running it, the idle smoothed out, and I began to notice that the motor had more power taking off from a stop. Also, the habitual ping that the motor had when accelerating under load went away completely. I've noticed some better gas mileage, but I haven't determined the amount of increase yet. Overall, it has definitely helped the 100K motor run better though, that is for sure.