* Fuel Injector Issues (Less Likely Immediately): While fuel injectors can cause ticking, it's less likely to *immediately* start after a fill-up. A more gradual change or a sound persisting after the engine warms up would be more indicative. However, if there was a sudden surge of fuel pressure during filling (perhaps due to a faulty filler neck or a very fast fill), it *might* momentarily upset the injector operation, leading to a short-lived ticking.
* Loose Fuel System Component: The most probable cause is something vibrating or loosened by the sloshing of the newly added fuel. This could include:
* Loose heat shield: Heat shields around the exhaust system are common sources of rattling. The added weight and movement of fuel could dislodge a slightly loose one.
* Loose fuel line or clamp: While less common, a loose fuel line or a clamp that's slightly come undone could rattle against something. The fuel sloshing around could exacerbate this.
* Something struck by the nozzle: During filling, the fuel nozzle could have accidentally bumped or dislodged a small component near the fuel tank, causing it to rattle.
* Fuel Pump (Less Likely Immediately): A failing fuel pump can make a whining or buzzing sound, but sometimes this can manifest as a ticking or rattling, especially under load. It's less likely to be *immediately* triggered by filling up, though.
* Exhaust System (Most Likely): Added weight from the fuel could cause an already loose component of the exhaust system to start rattling. This is a very common cause.
Troubleshooting Steps:
1. Listen Carefully: Try to pinpoint the location of the sound. Is it coming from the engine itself, near the fuel tank, or closer to the exhaust? This will narrow down the possibilities.
2. Check Under the Hood (Safely!): Once the engine has cooled down, carefully inspect the areas near the fuel tank, fuel lines, and the exhaust system for anything loose or out of place. Look for any heat shields that might be rattling.
3. Drive and Listen: Take a short drive to see if the sound persists. If it goes away after a few minutes, it's likely something minor that settled down.
4. Repeat the fill-up: If possible, try a second fill-up and listen carefully afterwards. This might help reproduce the issue and pinpoint its cause.
If the sound persists or worsens, it's best to take your Ford F-150 to a qualified mechanic for diagnosis and repair. Ignoring it could lead to more serious problems.
