My Focus ZTS, 2.3 liter engine, has started shuddering randomly when idling. I have run two bottles of fuel injector cleaner in two tanks. I got the fuel from two different convienience stores, so it's most likely not water in the fuel. I took it to AutoZone, no codes were being put out by the computer. Could a fuel filter be causing this? It mostly happens when I'm at a red light, it will shudder once, then maybe two or three times, maybe not at all. There is no rhythm to this madness.
Feb 24, 2010 at 5:23 PM