I change my fuel filters methodically. I do it at every oil change. I wondered about an injector, but I thought it would happen cold or hot. Also, if the tank screen is clogged would it not be rough running, as well, cold or hot. To test the tank screen I wondered if you fill the tank pretty well full & pull the hose off of the metal fuel line it should be a good full stream come out? It has been doing this same senario ever since I acquired the car. It's not a unliveable deal, but would be nice if it were smooth running when ldling hot. It does not seem to do it though hot if you shift into park. It's only like that when in drive and sitting at a stop.