I have a 2012 FX / 150 Super Crew. Currently it has approximately 90k miles and has been a great vehicle. It gets serviced regularly at the dealership.

Recently I was at a 4-way stop in a residential area with low speed limits. As I accelerated from the stop sign my speedometer went to zero (as if I turned the ignition off, but didn't). The engine started to rev from high to low with the vehicle wanting to surge forward. I'm guessing the fastest I was able to drive was about 25 m.p.h. I stopped and it seemed to be normal but once again when I started to accelerate it repeated the above. Once again I stopped, this time turning off the engine. When I started it again everything was back to normal. I did notice before I shut it off the "tow/haul" light was illuminated which has never been used. I thought maybe I accidentally hit the button on the shifter and that may have caused the issue.

Interestingly once the vehicle was operating normally, I engaged the "tow/haul" on the shifter to see if it would re-create the problem. I couldn't tell it was engaged as the truck drove normally. My understanding is that even when using this feature when the truck is turned off, the "tow/haul" setting turns off automatically.

Today I went out (and being aware of the "tow/haul" possibility) the vehicle had the identical problem as before, as I accelerated from a stop sign, the speedometer went to zero, the tach started to surge as well as the truck . The "tow/haul" light was NOT on this time. I had to shut off the vehicle 3x before I was able to drive it normally.

Any insights would be appreciated ................. before I take it to the dealership and get news that I probably don't want to hear.

Thanks in advance!

 

Something is wrong that the vehicle computer is picking up and placing the system in "Limp Mode". This is done to prevent any damage to vehicle components , yet allow the vehicle to be driven to a service facility. Turning the key off allows the system to reset, until the problem surfaces again and the computer places it in Limp Mode again.
Things like Electronic Throttle Control problems can produce Limp Mode as a safety feature. Best to have dealership check it over.

 

Is there a setting that I can adjust or is it something only the dealer (with the appropriate tech equipment) can diagnose?

 

If it were a performance problem, cleaning the throttle body might help.
There is definitely something going on that the system decides to prevent usual use.