[California98Civic]

If you installed an injector kill switch, you could kill the engine without interrupting any other functions, like radio or fan. When you key back on, you'd get the usual momentary radio drop-out, but then all would return to normal. If you want to avoid multiple uses of the key switch, you could install a push button start alongside the key switch. That way the key could stay unchanged in the "run" position while you cut and restart the engine. But this is really all overkill in an automatic transmission car, because you can't cut the engine in an auto trans car while rolling (EOC, the big FE gains). And since you'd still be using the starter motor. So your best strategy, most cost effective and least expensive with no loss in fuel saving benefits is just to key off and on at lights longer than 10 or 15 seconds.