1996 T-100 3.4L w/ TRD SC Engine Noise - Tap, Knock, other?

[jaguare22]

My 1996 T-100 w/ TRD Supercharged 3.4L has been making a ticking or taping noise for about 10K miles. Current miles - 115,000, SC install unknown, at least 100K on SC. The SC is noisy but in a much different way. This sound is more like valve tap, piston slap or rod knock. The only thing is I have never heard of any of these sounds being so specific to RPM's, load and throttle position. I have read post of similar noises but nothing has helped. I have been listening and trying different things for many months. Oil changes (weight changes also) and additives (honey oil) make no difference (such as change in tone or pitch). This is truck is auto, 4WD with side dump TRD stainless exhaust.

Here are the specifics of mine....(my heat shields are solid)

All these things must happen to hear this noise:
Must be under load - No noise while truck standing still.
Load must be light - Heavy acceleration eliminates noise. Throttle position is as light as possible - for me, normal acceleration.
No vacuum no boost - Vac/Boost gauge is always at neutral point when noise is heard.
Noise can be heard when engine is warm or cold, more when warm.

The noise starts at ~2600 rpm and last thru ~2850 rpm then stops abruptly. The noise will continue as long as all of these parameters can be maintained.

During normal acceleration, shifting occurs about 3K. When I start out there is no noise, truck accels normal, at ~2600 tap tap tap in time with revs, continues thru ~2850 just before shift point it stops. 2nd gear same thing. 3rd is a little different, rpm's being lower here but it is often heard while going uphill on freeway.


I have had it looked at, some say rod knock, another said it's the SC. I have also heard possible wrist pin or piston slap (piston skirt hitting cylinder wall)

Nice tries all but in my opinion we haven't got to the bottom of it yet. From inside the cab it sounds like a bad valve tap. I tried listening to it from under the hood with the truck on a dyno. I only heard it for a moment, not long enough to locate. I think the dyno guy was stepping into to much.

All opinions helpful, within reason, I am considering rebuild....
thanks jaguare22