4.7 liter V8, 4x4, automatic, 60,000 miles. Stalls whether idling or traveling down the highway at 70. No idiot lights come on. While coasting or stopped, cycle key from run to start and engine starts and dies. While stopped, put in park, turn key off and then normal starting procedure and engine starts and runs. Have had automatic shutoff relay replaced (only code that appears), all 16 spark plugs replaced, all 8 ignition coils replaced, PCM replaced. Problem started 14 days ago after routine maintenance at dealership (Upper 8 sparkplugs replaced, transmission service and engine oil change) Am at wits end! Any ideas?