Ever since about a week ago after i went cruising with some friends, my car has been running lean as soon as i start to move/drive the car. Car idles and revs fine.

Afr's are good at idle, 14.7-15, but as soon as i start moving/driving afr's act as if they are dropping but then shoot up to 15.5-16.5 while im not in boost. Only done it once but went in boost to see what the afr's would do and they acted like they were dropping, going as low at 12.5-13, but then rose and stayed at 14.7, once i saw that i let off the throttle.

Setup:

Stock ka, compression test came up 180 on all 4, test was done a couple days ago
arp head studs
felpro headgasket
s14 t28 8psi
370cc inj
isis fpr
walbro 255
Nistune(only adjusted some stuff, k constant maf timing etc, no tune yet)

Only parts that i can think of that could cause this problem are my fuel pump or fpr. Both have less that 1k on them. Other than that, vacuum leak maybe.

Full details on what has happened is here:
www.ka-t.org :: View topic - Help.. afr's lean after a cruise

Any help is appreciated.