Hey guys, tell me what you think of this situation:

I have an 8 that will only boost to 12-15 psi on cold start (not that anyone is trying to full boost cold, but you can tell that it is labored across the range). After 30-60 seconds it boosts normal, like a switch is flipped. It is consistent like clock work. I can't recall ever noticing this on an 8 before so I can't help but think it is a new development.
Also noteworthy that on cold start there is a random hiccup in the idle; nothing that can bee seen on the tach and nothing that makes the car feel rough, just an like audible cut out for 1/4 second. As the car warms up that goes away but it does persist after the reduced boost is resolved. If it happens more than once within a few seconds I'll see the AFR go rich for about 1 second (10-12:1) then return to normal

I can not find any boost leaks and the system holds 25 psi without issue. Wastegate actuator is very tight.
With regard to the hiccup, ignition system is all new (factory plugs at ~22, Spoolin up new COP kit). Injectors have had a pressurized cleaning and intake has been smogged out. Compression is 173 167 167 174.
As for modifications, standard 3" exhaust, 3.5" intercooler, 9 turbo. No tune since the 9 turbo, however conditions were present with the 8 turbo as well.


Any thoughts on the matter? I can't help but think they are related, however I'm blanking out here for some reason.

 

Well if anyone is curious I did some short run plotting today not allowing the engine to warm up and I found the front O2 sensor was skewed up about 200mv.... not real noticeable until you see it consistently flipping 5/9's etc.
I put a spare IX sensor in (only thing I had on hand) and got regular 2/8 switches again, so I put a new sensor in and the hiccup seems just about gone and the voltages are pretty stable in normal range.... a hair high for my taste, but far more acceptable.
Tomorrow morning will be the real test in case I just let it get too hot and it smoothed out. I'm sure it won't affect the boost, but if I get the hiccups out I'll be a pretty happy guy.

 

Well the hiccups are about 1/2 of what they were, still occurring though. No change in 12 psi cold boost obviously.

I went back and double checked my fuel pressure and I am showing a good amount of excess pressure, around 38 psi at idle (vs 33 spec). From the sound in the rear I am suspecting there is a 255 pump in there, is it possible that the pump is putting out pressure faster than the regulator can bleed it off? I'm curious as to how I got over pressure.