Messed up with acetone this summer, got consistently 270 miles per tankfull, but the oil started to thin, had to change it at about 2000 miles, not sure if I have a bad injector...now my engine ticks and the oil pressure goes below 50 under way and 30 idling, Mobil 1 only quiets it for about 700 miles.
Had a full tune up before summer (cheaper than gas!!!) fire plugs and cables.