It's usually the other way around - advance = better mileage, retard = worse. You had mentioned that you were running a P28 ECM in your car... P28s run fairly lean in stock maps, so that coupled with a little more timing will give you much better fuel economy. I usually set P28 equipped cars a little more advanced than stock and run premium fuel - usually 2-4 degrees more depending on mods... if you have a B series with higher compression usually less (higher compression means faster burn of air/fuel mix). I've seen mileage up to 39mpg on some D16s by doing this and get roughly 38 hwy with my modded D16Z6. As far as responsiveness goes - more initial advance will make an engine more responsive as long as you have enough fuel to compensate for tip in throttle. P28 stock fuel maps are this way - you can get the stock size tires to bark in 2nd gear on a P28 civic when you goose the throttle! :naughty: It sounds like your timing is too retarded on your car if you have poor throttle response - if it's too advanced it will start to ping noticeably, unless you have a knock sensor - then the ECM will just crank back the timing. If you feel like experimenting you could also try relocating your AIT sensor (intake temp) - sometimes you can squeeze another 1-2 mpg with that alone. A common misconception is that more is always better with ignition timing - too much timing will decrease WOT power and can also wear out your bearings in your engine, even if you don't hear detonation.