Diagnose ticking when coming off throttle

[toxicologist]

I have a prominent tick/click when the engine is cold. It is audible only when I let off the throttle and RPMs drop between 2000-1000. Between this range, the frequency of clicking correlates with RPMs. If I get on the throttle the noise goes away, even between 1000-2000 RPM. Can be produced in P, N,D (and maybe R?) Noise is easy to hear in the cabin or from the driver's seat with the door open. Not easy to hear with your head in the engine bay. I have seen threads related to manifold gaskets and non-OEM oil filters (changed to Ford filter and that didn't help), but none of the descriptions seem quite right.

PCM recently updated at Ford. Their diagnostics indicated the DPFE sensor was "slightly out of range" but not faulty. Could this cause the ticking?

Specs: 2002 Explorer Eddie Bauer, 4wd, 4.6L. 170,000 miles. Rebuilt motor, new torque converter, new wheel bearings, new rear struts, new tires and rear diff rebuild all at 165,000 miles.

Any thoughts? Thanks in advance.

 

[Bobmbx]

Sounds like a lifter needs to be adjusted or replaced.

 

[Bobmbx]

Use a shade tree stethoscope (short broom handle) pressed against the valve covers and your ear when the engine is running. You should be able to pinpoint the noise if its the valve train.

Here's a brief to help