Legacy Turbo Hesitation and CE issues...

[gt2.5turbo]

So I need some ideas on how to fix/trouble shoot my problem:

Background:
1993 subaru legacy turbo sedan.
Stock ECU, injectors, sensors, wiring harness
ej20g with 20g DOHC heads
Stock ignition system
vf22 externally gated running 8psi
Custom Parallel Fuel Rail System regulator set to 35-38psi at idle

Ran Great for about 6 months and the problem first appeared on an extended highway drive around christmas.

Problem:
1. Car develops a bad hesitation/bucking problem once warm approx 15-20mins of drive time. Only when the car is warm. It
is present partial and WO throttle
2. Cannot Clear engine codes: Tried both the step by step clear process and extended battery pull.
3. No timing advance---> very similar to "safemode" feel in other cars
4. Idle hunting once warm however it is not rythmic
5. Tach randomly gets jumpy or spikes. This just developed within the last attempt to figure out the problem

Investigation So Far:
1. Initially thought to be bad gas: fuel filter and gas were changed: no change
2. Maybe the plugs where fouled from bad gas: changed but no improvement and old plugs look fine.
3. Pulled CE Code: 22,23,24,33,35(expected as the valve is no longer installed), and 45
22: knock sensor
23: Air Flow Sensor
24: Air Control Valve
33: Vehicle Speed Sensor
35: Canister purge vavle
45: Atmospheric pressure sensor

4. Changed out TB: first TB was misadjusted when the car was orginally finished and the idle was horrible so it was
readjusted so i replaced it with a known good, properly set TB. Didnt change anything.
5. Checked IAC for sticking or misadjustment: All seems fine.

Next Steps:
1. Start replacing sensors and checking functionality of all sensors that have codes present.
2. Source ECU to borrow to eliminate a bad ecu cause.
3. Tear into the top of the motor to check for wiring issues/vacuum leaks etc.


Any Suggestions?!?!?! What gets me is how the problem reacts to heat and not being able to clear any codes from the ecu. It ran fine with this turbo and fuel setup with safe AFR's when I first got it running.

Let me know if you have any ideas!

thanks!