2008 Ford F-450 SD engine problems

Have had acceleration issues with this ford f-450 since april of 2010, the first time the driver was able to stop the vehicle without incident but the engine blew up when he put it in neutral to stop the vehicle. It was at the ford dealership for 6 weeks, I retrieved the vehicle, while on the way home the engine failed again, it was towed back to the dealership. 1 week later I retrieved the vehicle again, 2 days after that the accelerator stuck once again while hauling a trailer loaded with a rental trencher.

Tl* the contact owns a 2008 ford f-450. While traveling 55 MPH, the contact noticed that all of the warning lights were illuminated on the instrument panel. Moments later, the vehicle stalled and could not be restarted. The vehicle was towed to the dealer where the turbo head was replaced. Prior to the most recent failure, the turbo head had been replaced three times. The current mileage was 70,000 and the failure mileage was 32,000.