ive used acetone in my 5.2L FI dakota before and it has the computer reprogram for hot tuning with regular gas. I was adding 3 oz acetone per 10 gallonsof regular gas and it sure sounded better and idles smoother and felt like rfeal good premium gas. and th e gas milage was indeed a fiar spot better. id say it works. and i got a 16 oz bottle for 5 bucks, id say that prolly makes up for the difference between regula;r and premium and crappy or better mileage after its all used.