Just bought 2003 F350 power stroke 6.0. Superb condition. Will not restart after driving and dummy gauges reading temp within allowable range. Engine doesn't overheat when driving. Have not pulled trailer. If I let engine cool about 40 minutes will start immediately. Same issue once I go down road some more. Help greatly appreciated. Look silly in beautiful dully in 105 degrees, sweating up a storm, waiting to restart.