I'm trying to figure out what direction to go in next. I have an 03 Z06 that I bought last year with an unknown number of mods on it.
From what I can tell so far it has:
iron block (unknown size)
prc cylinder heads
long tube headers with x pipe no cats
92mm fast manifold with ls2? throttle body and drop in k&n filter
Sometimes it drives perfectly fine and some days it will drop into reduced power mode more than once on the same trip. Seems to be getting worse lately and the car sleeps in an air conditioned garage. Also I've never washed anything under the hood, I don't think its even been driven in the rain.
It has dtc P0332 - Rear knock sensor
P0442 evap small leak
P1220 Tp sensor 2 circuit
P1221 Tp sensors 1, 2 performance
Tcs : C1278 H Tcs temp. inhibited
C1282 H yaw control bias system failure
C1283 H Excessive time to center steering
C1296 H Master cylinder pressure cylinder circuit
U1000 H Comm. Malfunction

1. I've already tried replacing the Tac module with one from a vette with 4k miles on it. Didn't make a difference.

Checked the connectors to make sure they're clean and tight, checked pin fitment, checked the Ls2 throttle body conversion harness.
Checked the voltage on the accelerator pedal with a scan tool.
I don't have a scope or an analog volt meter to check for dead spots in the throttle body.
So that's where I'm at currently, I'm not sure if I should find another throttle body or get a new app sensor??
If I wanted to buy a new throttle body where would I even get one? Gm doesn't seem to make them anymore and is there a reliable aftermarket available?

 

With the 2 TPS DTC’s I’d check the signal voltage of the TPS sensor at idle and WOT with key on engine off with your scan tool...let me know what you see !!...I see your a tech...you really should have a scope these days...I wouldn’t leave home without it...it is just as valuable as a scan tool for diagnostics and maybe even more so..what scan tool do you use ??

 

Yes I definitely need a scope but I wouldn't know what I'm looking at, known good signal vs bad signal. I need to go back to school to learn it in depth.
Well the scan tool I have access to at work is a Autel Maxisys and a cheapy Launch scanner with limited abilities. The only thing I have here at home is my dvom.

 

There are LOTS of YouTube videos where you can pick up this labscope info. Secondary ignition has a not to bad learning curve and in cylinder pressure transducer analysis is pretty steep...when you look at a lot of good signals you will know what bad is !!...is the P1220 and 1221 current or history ??...these pics below are what my APP/TPS looks like at idle and WOT. Your voltages should be pretty close.

WOT

IDLE

 

The pcm codes are both current and history. I won't be able to get the car to the shop until later this week possibly to put the scanner on it. So I back probed with my dvom. These are my results: Key on engine off

Blue wire Tp sensor signal 1 : Idle 1.337 Volts Wot 4.46 Volts
Pink wire Tp sensor signal 2 : Idle 3.70 Volts Wot 0.565 Volts

Dark blue wire App signal 1 : Idle 0.70 Volts Wot 2.74 Volts
Light blue wire App signal 2 : Idle 4.35 Volts Wot 2.30 Volts
Dark green wire App signal 3 : Idle 4.03 Volts Wot 2.80 Volts