Hi guys

I have a 1999 f150 with the 5.4 litre engine with 120000 kms on the motor.Yesterday as the wife was leaving home i noticed a tick coming out of the motor as she was leaving.Took the truck for a ride today, the noise seems to disappear as you increase speed or you just can't hear it at increased speeds. Any ideals on what the promblem is and how to solve it would be greatly appreciated.

Thanks