MAS overrun at 13psi?

[COspeed]

I recently swapped out my original MAS that had no lower honeycomb, with a stock one. I was trying to fix my weird fuel trims and gas mileage. The new MAS helped with my fuel problems, but is now causing some other problems. The car went from running fairly lean, to running pig rich. More importantly, I'm hitting MAS overrun in the upper RPMs on only 13 lbs of boost. This seems a little out of the ordinary to me. I'm also at a high altitude (5300 ft) and it has been pretty warm lately (75-80*). I have a datalog of the most recent occurence if anyone is interested...

Relevant mods are:
3" turbo back exhaust
ported 14b, o2 housing, 2g manifold
Walbro 190lph pump
Fuel system upgrade (filter, SS line, -6 AN fuel rail inlet)
boost controller @13psi

 

[DrZiplok]

Boost leak.

 

[kpt4321]

I agree with the bag man.

A boost leak creates an artificially high airfow across the MAF, making overrun and fuel cut much more likely.

....Kyle T.
93 TSi AWD "TURBO4"
14b - 12.8 @ 108

 

[COspeed]

Yeah, I considered the possibility of a boost leak, but the weird thing is that none of this was happening with my old hacked MAS. Once I put in the new MAS with everything intact (except silencer) it started to stutter and buck at higher RPMs. A datalog of the most recent occurance can be found here:

http://ucsu.colorado.edu/~hickeye/log.html

the weird stuff happens at the 14:12 and 14:48 minute markers...

Thanks!

(the file is a TMO log file)