Fuel Problem COS-3 E40

[Forcefedperformance]

We Are having a problem with a 06 GTO going lean for some odd reason and we are having trouble finding out why its doing it....the car is a 6.0 stock bottem end with ETP LS1 Heads,Cam,APS Twin Fuel Pump,60LB injectors,Aeromotive aeromotive regulator and a F1 A Procharger.

We was making about 5 PSI at 5800 and everything was fine so we changed the pully to make some more boost and now whenever we hit about 5000-5200 rpm no matter how high we make the boost ve numbers it will allways go lean in the same spot. We are watching fuel pressure and not seeing a drop so we are a little confused.

Could someone please take a look the file and see if we are over looking something?

Thanks ,Bill

[GMPX]

Bill,

Have you logged what the Airflow g/cyl is at this point? If 'for some reason' it is dopping a lot you will see the lean spike and probably timing go up too.
Log the PID GM.APCYL_E40_DMA

Cheers,
Ross

[Forcefedperformance]

Your right our APC was droping...but why?

Here is the data log for that car.