I've been running acetone in my CJ for a while now. I believe I can tell a difference in power because I can use 5th gear again! The engine doesn't seem to labor as much on the Hwy at 60-65 in 5th. On a recent 600-mile trip I averaged 22 mpg. the highest reading I got was 23.7. This was cruising at 60 - 65; I don't care to go faster than that in the CJ. On the way home I filled up twice without adding acetone and each time the mileage dropped a little. I got 20 mpg on the last leg. I'm convinced it helps. I will keep using it and experimenting. I've been adding about 2 ounces per 10 gals. If I drove the YJ much I'd put it in there too! <img src="/forums/images/graemlins/cheers.gif" alt="" />