Ford Super Duty (1999-2016) :: 2014 F250 6.2L Gas Engine Stalls At Highway Speeds

2014 F250 SuperDuty 6.2L gasser, x-cab long bed work truck. 105k miles, original owner, 1 driver, mostly highway miles, well maintained and super clean truck.

First issue occurred at 83k miles, Aug 2016. Warm summer day climbing I-70 in CO, slightly loaded, and just entered the Eisenhower tunnel (11,150' altitude). Lost power, no RPMs - not running, I put it in N and rolled as far as I could. Hazards on and no-where to pull over, hugging the wall and blocking one lane. Power OK - will crank, no fire. 1/3 tank on the fuel gauge and >100 miles distance to empty on the trip computer. Tunnel rescue shut down traffic and pushed me out into the daylight.

After waiting an hour to fill our paper work for disabling the interstate tunnel I returned to the truck which quickly started. No symptoms, no lights, no codes. Topped off the fuel tank after a easy 15 mile drive downhill. Drove another 800 miles symptom free to my destination and checked it in at the dealer. At this time a check engine light had finally illuminated - PO420. I shared the story of stalling out at highway speeds with the Service Writer. Dealer replaced the cats, confirmed fuel pressure OK, computer condition OK, serviced the trans (at my request).

No symptoms reoccurred during the next 20k miles until last weekend. 105k on the OD now. Heading to Flagstaff, AZ on I-40 in similar conditions. Hot, AC running, climbing in elevation, slightly loaded, running on the bottom 1/3 of the fuel tank... Died while cruising at 79 mph. Well, at least this time I wasn't in a tunnel and had a shoulder to pull off on. Deja-Vu - full power, radio on, no engine lights, gauges normal, fuel reads over 1/4 tank, >100 miles till empty on the trip computer - won't start. Cranks, but no fire. Some sputtering during start attempts must have triggered the next trouble code.

Opened the hood, removed the gas cap, let it vent and cool for about 30-40 mins while I took a walk. Returned to the truck which easily started and let me drive to the next fuel station, 30 miles away. This time the check engine light stayed illuminated. It took 24 gals of fuel. Drove 3 more hours and almost 200 miles without symptoms - check engine light still illuminated keeping me curious and fully alert along the way.

Got the codes pulled at a parts store that was open on Sunday. PO300 & PO301. Random misfires and cylinder 1 misfires. Sounds consistent with poor fuel supply? Spent the rest of the day searching forums for any clue to this highway stalling. All I came up with was to clear the computer - disconnect battery, turn lights on, wait 15 mins, reconnect battery, start engine, apply brake, drive, etc. This and another full tank of gas gave me enough courage to set out on my trip home.

Next occurrence was just outside of Santa Fe, NM. Similar conditions again: Hot day, AC kicking, Interstate travelling about 80mph, slightly loaded, climbing in elevation, fuel tank just below half - stalled out. Repeat previous learned routine. Open hood, vent gas cap, walk it off for 30 mins, return to truck, start it up. Drive to next town and top off with fuel about 30 miles away - only took 16 gals! Made it home 4 hours later without stopping. No repeat symptoms, no check engine lights.

The next day a code - PO420. Catalytic efficiency below threshold.

Quick recap:

6.2L gas engine stalling at hwy speeds.
Cruising between 65-80mph
-Interstate travel - no stops between last fillup and stall.
-Warm weather, AC on
-Running on bottom ~1/2 tank
-climbing in elevation, slightly loaded

To clarify: slightly loaded - no trailer, maybe 1,500 lbs bed cargo, mostly wind drag. The most I have pumped into the fuel tank is 29-30 gals or so. I assume I have the 34 or 35 gal tank. Never seen the calculated "distance to empty" below 40 miles.