2000 Izuzu Amigo ticking noise
 

Hi everyone, new to the site. Thanks in advance for your input. My friend recently bought a 2000 amigo v6 2 wheel dr and the car runs great. He has driven it for about three months now and about two weeks ago it started making a clicking/ ticking noise in the engine compartment, when the vehicle is going 50+ and he starts to decelerate. The noise seems to be only after 50mph and only when the gas pedal is released. It sounds in my opinion like a spedo cable going bad. But I don't know much about this car. Please advise. Thank you