Ok. I've had my 4.2 (3.8 :0)) for about a year and a half, and so far it has been working great. Now though, there is this noise coming from the engine. Its only when in reverse and while at very slow speeds. (5mph or less) Its a ticking kind of sound. Kinda like if you put baseball cards on the spokes of a bike. Like that, but it isn't constant. One second it will be kinda loud and I'll sit at idle for a second, it will go away, then when I take my foot off the brake it starts up again until I give it some gas. Has anyone had this problem? I've got about 73,000 miles on it. I don't know hwta it is, and I don't feel like paying some schmuck $50 bucks just to figure out what it is!

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1997 Ford F-150
4.2 L V-6
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2 Rockford Fosgate DVC HX2 10's
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GTS headlight blackouts
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My guess would be U-joints.

 

Your not draggin some old lady are you? Could be her perl necklace clankin around under there?

I would check yourself and then pay the $50!

 

As Dennis said it sounds like the u joints
they will make a tick or clacking sound when
they are worn out and can also cause vibration if one is froze up.