d16z6
block: vitara with eagle rods and acl race bearings
Head: ARP studs, skunk2 valve train, stock cam,skunk2 valves
timing is good
Turbo: 60ar cold 63 hot 2.5in intercooler
walbro 255 fuel pump, 320 supra injectors
chipped p28

only have an a/f ratio gauge
running little bit rich at idle
the problem i have is when i accelerate/WOT it goes rich then instantly lean until boost kicks in around 3psi up it goes back up rich then when it hits full boost at 7psi and almost to 5k rpm it instantly goes really lean and then it lags

i dont know what the problem is
it didnt do this before until last week
i was thinking maybe bad/lazy o2 sensor? bought last year
CEL on for VSS but is intermittent so i ran it b4 cel comes on and still same problem

ive had two set up on two different motors
with the same 320cc injectors and the same tune that runs rich when WOT.

 

tune, tune, tune.

are you using a wideband? the lightshow narrowband gauge is useless for any sort of diagnosis.

 

get some bigger injectors.
my 370cc's are maxed at 10psi on a tiny 15g.

 

well it was tuned and was running good for a month
how can it suddenly go bad?
my last set up with the air/fuel gauge worked fine

 

this is 320cc at 7psi
had two set up with this and it supports fine
my tuner said

 

Could be sooo many things.

Likely it's the tune, but it could be:

Fuel pump or Injectors, (they could be clogged or failing, keep in mind they haven't made supra's for YEARS so they're definately getting old)

ANY sensor referenced by the fueling maps

Wiring to ANY of those sensors or to the injectors

BUT if it's happening in a predictable and constant way then I would DEFINITELY look at the Tune first.