ok...for some reason...my car is leaning out way to much and not holding idle. i had my turbo setup on my car now for atleast 4 months and havnt had any problems with it till now. i've been runnin with a rc 310cc injectors, fmu, and a walboro 255 fuel pump. my air/fuel has been tuned by my vafc on a dyno. anyways, on my a/f gauge...it just read that it's leaning out way to much and it having trouble to keep idle. it drives and boost fine...but once i stop..the idle just drop way down to 300 to 400 rpm. and also...for some reason..my fuel pressure just bumped up to 50 psi at idle..before it was just sittin at 40psi. and there's no cel for my o2..so i dont know what's going on.

 

first thing....get a wideband o2 reading and not the crap narrowband VAFC a/f ratio reading.
i had similar problems as you about a month ago and i ended up replacing various parts that worked fine. it turned out to be the stock o2 sensor crapping out and sending wrong values to the ecu, thus leaning out the injectors.

also,,...is that walbro 255 an inline pump or intank?


edit: forgot to mention that the car wasn't chucking an o2 CEL either...

 

yeah..i replaced the o2 and now it runs pretty good. thanks for the advice. and the 255 is a intank.