I have been over all sorts of stuff and I am finally going to post on here and see what feedback you guys might have.
Car: 2002 WRX, 2.5L Sti block, 2.0L heads, stock head gaskets, 900cc injectors, aftermarket fuel rail and regulator (same pressure as stock), VF39 turbo at 15psi, silicone turbo intake tube, short ram intake, AEM cone filter, large billet MAF housing, TGV deletes, custom reflash tune, brand new Walbro 255 pump, brand new fuel filter, brand new Oxygen sensor, brand new OEM ignition coils, good plugs gapped at .028", full catless up/downpipes, 3" exhaust.
Ever since I got the car it has idled poorly, but always ran fine once off of idle. In the process of diagnosing the bad idle, I replace several parts (coils, O2 sensor, etc).
But recently, it has developed a terrible bog when I give it any sort of throttle. major hesitation, and often some popping from the intake (mini back-fires). This has gotten worse over the last week or so, the car is now hardly driveable.
Here is what i have checked:
1. replaced the MAF with a known good MAF
2. replaced the MAP sensor with a known good one
3. checked plugs (tips are clean, no fouling, they look descent).
4. pressure tested inductions system for major leaks, etc, nothing.
5. Cleaned both MAF's with sensor cleaner, re-tried both of them.
6. Flow tested injectors, all flowing at 900cc (de-capped stock injectors) at 3Bar.
7. Installed a fuel pressure gauge, shows exactly specified fuel pressure (3 bar).
Just today I installed a new Walbro fuel pump, problem did not change.
I am not getting any smoke out the tail pipe.
No engine codes (I have the evap, TGV and secondary O2 DTC's turned off).
The only damn thing I have not checked is the throttle position sensor. But I will need to borrow a live-data scan tool to check it, I will do that in a few days.
Any other ideas of what to try???? It is killing me!