**Originally accidentally posted in the Gen1 Forum**

Update 09/07/16 - PROBLEM SOLVED
-- It was caused by a faulty diverter valve. I installed a GFB DV+ which replaces the piston and diaphragm and it now is back to holding boost. It shows up to 16PSI @ full boost and no longer cuts out to 8PSI.

Hi guys/gals

I've got a stock FJCW which just had the timing chain and de-coke to fix the dreaded pinging issue at low RPM WOT.

While I had the issue, I babied the car, now the car is fixed (mostly) it's a pleasure to drive again and you can really open up the throttle.

The odd thing is, I seem to get a boost cut at ~5000RPM where it drops from 12.9 PSI down to 8 PSI.

Ambient temps, coolant temps are good. It doesn't spike up before it drops or anything. It's just like a flat spot at that RPM range.

I'm using a P3 to measure boost off the MAP sensor, so it's not 100% accurate but I know it didn't do it before.

No software updates or tunes have been applied to the car and it will hold 12.9 PSI of boost when under low load for as long as you hold it, so I don't think it's a boost leak.

Has anyone experienced similar issue?

No pinging, or codes are logged on the ECU and no check engine light flashes. I've also changed out the coils and plugs to make sure it's not that.

Any suggestions/experiences/hints are appreciated.

Thanks in advance.