My 2003/F150's been making ticking sound since 30K miles. More noticiable now after 90K. Sound most prominent with load on engine between 700-900 RPMs. Ticking goes away above 900 rpm. Noise sounds like it is coming out of the exhaust ports at the manifold (both sides). Sounds like a weak or collapsed lifters. Any recommendations?
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Does the ticking occur in neutral, sitting still, with engine at idle?

Based on what you describe my first guess is oil pump. Not a failed oil pump, but a ticking sound that is characteristic of the oil pump in the 4.2.

I have heard it on both of my F150s w/ 4.2 and it has never caused me any problem (over a total of 370,000 miles between the 2 trucks)

A mechanic's stethoscope would be a good tool to use to try and isolate the source if you really want to be sure.

You might in fact have a problem with the valve train, but I know a ticking sound is common from the oil pump and would hate to see you dig into it if there really wasn't a problem. But, you'd also hate to assume there wasn't and then be wrong :-o

Let us know what you find.
Thanks!

 

No ticking at idle (800-900RPM) in neutral, any RPM above 900 while in gear (standard) or cold before operating temperature is reached. Easily heard when letting out the clutch and the RPM drops between 600 to 900rpm. Engine runs strong, no ticking or knocking during acceleration or highway speeds, 22-24 MPG on the highway (3.08 rearend). Great oil pressure, using Castrol 20/50. Is there a TSB out on the oil pump? Can the oil pump tick be isolated/ confirmed? Will changing a ticking pump fix the problem or will the OEM replacement do the same thing?

 

Could it be as simple as an exhaust leak, I don't know exactly what your noise sounds like but it wouldn't hurt to check. And one more thing These engines are designed to run on 5W-30, I believe running it on 20W-50 is unwise but its your truck, just my $.02. Hope its not anything too major.
-Brad

 

You said it does it while letting the clutch out.. throwout bearing bad? We have an old GMC that used to do the exact same thing until we got the throwout bearing replaced. Does it still "tick" if you press the clutch pedal to the floor?