[bernteck]

Water in the gas may cause random misfires but more likely with vehicle moving and should clear soon after stopping. An injector wire intermittently shorted to ground. if the engine is misfiring at idle you can remove the injector wire connectors one at a time to determine witch cylinder is misfiring then inspect that cylinder components. OEM spark plugs (Bosch spark plugs will likely run very poorly in this engine). Also check for wire harness chaffing by the oil filter (sharp engine corner) and the purge solenoid bracket.