I have an engine sputter that is starting to drive me crazy. It is a 4 cylinder auto. When I start it up cold and drive it, it'll run perfect all day. When it is hot, turned off and started again when still warm the engine will always start great; run for about 10-15 seconds with no problem and then it will sputter and lose power. I take my foot off the gas let it coast for a few seconds and then hit the gas again and it will accelerate and run great until the next re-start. It'll only sputter right after starting up warm. I suspect I have an exhaust leak somewhere because it has gotten a bit louder. Could that be related to the sputter problem? Any help would be appreciated!