When driving the engine sometimes cuts out at idle, when slowing down or at a stop.

Check for vacuum leaks, then the idle air control valve. Thanks vacuum seems OK, I accidentally touched the battery terminal causing a momentary spark (when removing a spark plug) could this affect the ECM? Possible, but not likley, With 214,000 miles I would suspect fuel or air fuel problem, like dirty fuel filter, dirty throttle body, or the IAC