Current Mods to car:

17% alta pulley, new belt as of 4500 miles ago.
Alta CAI without the silicone tube.
JCW Exhaust
Defi CR Advance Gauges

VGS mod

When I first installed the VGS mod my car ran great, boosted hard and peaked at 18psi at redline.

randomly about 2500 miles into it, it started surging slightly at 2500-3000rpms giving me a Un-confirmed p0171 code for being lean.

I'm not sure if I'm boost leaking as i still hit 17psi and it holds steady.

any ideas?

-B

 

Just double check all your connections & for leaks, esp make sure the line to the fuel regulator is tight. Sounds like there's a slight vac. leak somewhere.