I have a loud ticking from what seems to be coming from an injector. What is the sign of a failing injector and what could this ticking be?

When/where exactly does the sound happen? Does it change with rpm?

It's more pronounced when the engine is cold but, the ticking is constant (however it does quit for a few seconds here and there). This isn't the normal ticking you hear in a healthy 3.0, it's louder. The noise seems to be coming from an injector but not quite sure (I used a screwdriver as a stethascope). Sounds like a mechanical valve way out of adjustment (I know these engines have hydraulic valves, not mech ones).

mine does the same thing and i would like to hear what it might be also. my truck sounds like a train wreck driving down the road and id like that to stop.

i would check all the spark plug wires. check from the boots at the distributor all the way to the plugs. look for cuts, breaks or any way that the electricity could be arcing to a ground. an ingnition coil makes enough voltage that when jumping through the air to ground, it makes a loud clicking noise.

Exhaust leaks make a ticking noise as well. Have you tried fuel injection cleaner to see if it helps?

well for mine a spark plug backed out and shot out of my engine. i retapped the hole, but ever since it has ticked bad and makes a weird grinding noise upon acceleration.

I've isolated each spark plug and wire at the dist cap and the sound persisted. I can't quite put my finger on the source of the noise but it seems to be coming from under the air manifold (the aluminum intake on an EFI system) that sits on top of the whole engine. And the only thing under there is injectors. I feel a matching "vibration" in the fuel injector system (pressurized pipes near throttle body). So this tells me it's most likely a fuel injection problem.
I don't think it is an exh. leak. The location of the noise and the pure "metalic, mechanical" nature of the tick leads me to exclude thos problems. Although I did look for "blue flame" in the dark and saw nothing (not that this is all the reliable).
I used injector cleaner a few months ago. What does a bad injector sound like?

Check the fuel pulsation dampener. That little metal canister on the right side of the motor next to the plenum is what always clicks on me.

Did you ever figure out the problem with the loud ticking? Mine just started doing the same thing after I changed the oil. (10w30) Exactly as you described (same area)definately not an exhaust leak, and I just put in new plugs/wires, etc.. So... Any Ideas?