A few weeks ago we had our F-350, 6.7L, heavy duty diesel in for an oil change. As we were leaving the lot the truck lost power and gave reduced power and check engine light messages. So we went back to the service bay and they said it needed to have new software installed (or reset?). It was fine after that till today - just a few weeks later. We were on a major busy street when again we got the reduced power and check engine light. We limped home doing 12 to 20 MPH with pedal to the metal. It seemed to surge back and forth between those speeds. Not only was that very annoying - it was a definite safety hazard. Rude drivers blowing horns - and I am sure that wasn't all - was a bit distracting. Any idea on what could be going on? (It is scheduled to go to the shop in a couple days.) Oh - - The DEF tank is half full so that isn't the problem.

 

Same **** happened to me at 1500 miles. Ford replaced the ECU under warranty.

Thanks, Ford.