leaning out under boost

[Ethan]

I have a 90 240sx with a s13 red top in it and everything is pretty much stock. stock boost, front mount, walboro 255, and a RFL BOV. for about the first 2to3 min. i drive it everything is perfect. It goes straight to 8lbs. of boost and my airfuel gauge reads rich. The after the 3 min. when the car comes under boost it goes lean. This happens around 4500rpm. I am totally stuck and i need help so any idea's would be appreciated. :confused:

[Jsquared]

get on a dyno with a wideband O2 sensor. now. and sell that AFR gauge and use the money for something that works.

[nrcooled]

It's supposed to lean out. Initial WOT throttle will cause a rich condition and as boost builds the extra air forced in will compensate for the rich condition and run propperly (not super lean but it will lean out some)

if I had my dyno chart I would show you

[Ethan]

when the car leans out it goes full lean and breaks up and misfires. I know the car is supposed to go a little lean under full throttle. My problem is that the car drives perfectly for the first 3 min. then after that is when i see my problem.