Why does my Ford F-250 knock when I fill up?
Why does my Ford F-250 knock when I fill up? In the case of both the F-250 and and the F-150, the engine computer will retard the ignition timing if it senses pinging. Figure 1. Use the manufacturer's recommended octane level in your vehicle at every fill up. If you are using the correct octane level of gasoline or using an octane booster and knock persists, go on to Step 2. What to do when your Ford truck starts knocking? Return the engine speed to idle and verify if the knock returns. If the noise intensity is more than a...