Most Likely Culprits:
* Fuel Pump: This is the prime suspect. The turning maneuver might be causing the fuel pump to lose prime or experience a temporary failure due to low fuel pressure. When the truck sits, gravity may help refill the lines, allowing a restart after a delay. A failing fuel pump often makes a whining noise when the key is turned to the "on" position (but not cranking).
* Fuel Filter: A severely clogged fuel filter can restrict fuel flow enough to cause the engine to stall, especially under load (like turning). This is a relatively cheap and easy part to check and replace.
* Wiring/Connections: A loose connection or damaged wiring in the fuel pump circuit can interrupt power intermittently. This is less likely if the fuel pump is making noise, but should still be considered.
* Inertia Switch (Fuel Shutoff Switch): This safety device shuts off fuel supply in a collision. It's usually located under the dash or in the engine bay, and sometimes gets tripped unintentionally. Check for a reset button.
* Lift Pump (if equipped): Some 7.3L Power Strokes have a lift pump to pre-fill the high-pressure injection system. A weak lift pump can lead to similar symptoms. This is less common but possible.
* HPOP (High-Pressure Oil Pump): While less likely to cause an immediate shutoff and delayed restart *specifically during turns*, a failing HPOP can cause fuel delivery issues under certain conditions. This is more common with hard starts and poor performance in general, rather than sudden stalling.
Troubleshooting Steps:
1. Check the Fuel Level: Ensure you have sufficient fuel. A low fuel level can cause similar symptoms, particularly if the fuel pickup in the tank is getting exposed.
2. Listen for the Fuel Pump: Turn the key to the "on" position (but don't crank). You should hear the fuel pump whir for a few seconds. If it's weak or silent, the fuel pump is likely suspect.
3. Inspect the Fuel Filter: Check the fuel filter for visible damage or excessive dirt. Replacing it is a preventative measure even if it doesn't seem visibly clogged.
4. Check Fuel Lines and Connections: Look for any cracks, leaks, or loose connections in the fuel lines running from the tank to the engine.
5. Check the Inertia Switch: Locate and reset the inertia switch if present.
6. Test Fuel Pressure: This requires a fuel pressure gauge and some mechanical know-how. Testing fuel pressure will confirm if the pump is delivering sufficient pressure. This is the most conclusive test, but you might need a mechanic's help.
Important Note: Driving a vehicle with intermittent fuel delivery is dangerous. Continue driving only if absolutely necessary and proceed with caution. The best course of action is to have a qualified mechanic diagnose and repair the issue. Ignoring this could lead to severe engine damage.
