Engine lunges randomly, then jerks repeatedly
 

My F-350 blew the engine at 31,000 miles, one month out of warranty.Since then, it lunges forward once in a while, even at a stop. And often it jerks repeatedly for several minutes. It can be while decelerating or at highway speeds. Ford gave up as they can't get an error code. I had an EDGE installed and the problems remain, so it wasn't the computer. Any ideas would be appreciated. The EDGE does show 2 errors: P0470 and P0603. Any connection?