crytesy

Hello All,

I took a trip this week to the mountains and noticed a sound tha I had never heard before.
Here is the scenario:

• 2007 F150 5.4L
• Engine was at operating temperature (only makes the noise at operating temperature)
• noise only occured at low speeds when I was feathering the gas peddle at 15-20mph.
• the noise sounded like chain lash....almost sounded like a diesel.
• I could mimic the noise in neutral at 1200-1400 RPM when the engine was hot.

Is this normal? I don't normally feather the gas peddle which means i've never heard the noise before.

Thanks in advance for any input.