[soxnail]

This has been going on for while, just has not been enough to chase till now.
When the car is in full boost for the first time in the day (it is at operating temperature) and it does not matter if I have been driving for 10 minutes or an hour, as soon as it goes into full boost for the first time at 12 psi or more it starts to act like its getting a fuel cut, hesitation or surge. This is also reflected by the AFR going leaner, may even throw an AFR lean error (AFR getting to 13:1 while over 5 psi in my case). This only happens once, the very first time, after that the car behaves as normal, boost to 12 + psi, AFR 12:1 or lower and smooth power no hesitation or any thing.
-Fuel injectors were cleaned and flowed a month ago.
-Spark plugs are new 6 months ago, I have pulled them before using the car first time , clean no fouling etc.
-New rotor in the distributor 6 months ago.
-New TPS 6 months ago.
-Fuel pressure stays above 50 psi the whole time.
-New FPR and dampener about 6 months ago.
-New fuel pump and filter about 6 months ago.
-Air flow sensor stays consistent.
-Fuel delivery meets the specs.
-New DME relay.
-Pressure testing the system at 15 psi, could not find any leaks.

I am some what mystified....Any ideas ?
Thanks Sox