Help fix Bucking 6.0l m6 silverado

[Black02Z71]

I'm having a hard time getting rid of the surgeing idle, and bucking problem in my friends truck. It used to do it with the auto trans, but it was liveable, but now he put a 6 spd in there, and now it has become violent.

with the clutch fully out, and driving slow, (creeping) the engine will surge, and he whole truck buck vilolently, as all the slack in the driveline is taken up, and off again.

I've tried adjusting everything to do with the idle, nothings made it better so far. I'm new to idle tuning, and don't have much time to play with it, so I really don't know what I'm doing.

2000 silverado reg cab 2wd
LQ4 6.0L
220/224 low lift 114 lsa comp cam
thorley tri y's
T56 6 speed manual
4.10 gears

The waves in the log file at low speed is the bucking part

[Black02Z71]

Do I need to drill out the TB?

The tps voltage is .69v closed, and the IAC position when fully warm is around 20 counts.
Back the screw off, and drill TB?

Thanks

[WS6FirebirdTA00]

That is a high TPS voltage for closed throttle. Having any issues zeroing out TPS?

[Black02Z71]

No the tps % is zeroed, I was using the throttle screw to help stop stalling with the cam, instead of drilling the tb. So I did the reset on the tps.

will it still screw things up with a high tps Voltage, even when the TPS % is 0?

[WS6FirebirdTA00]

The only issues I had was with the TPS being over 0%. I am not sure what voltage is not good, can't remember right now.