spiking lean

[twisted99s10]

hey guys, im having a bit of an issue. i have an s1 rb25, with walbro 255 fuel pump, q45 maf, fmic, 3" exhaust. "tuning" it with a safc II and a wideband. every once in a while it would "blip" lean for just a split sec then run fine. lately when im driving it will spike lean for several seconds, even sometimes completely stall out. its acting as tho it isnt receiving fuel. the fuel pump is continually running while this happens. all of the wiring still checks out (no bad connections). iv replaced the fuel filter, replaced the vacuum line to the fpr. checked and rechecked everything, im completely lost. any one have any ideas?

a little bit of other info, at idle it often gets stuck running either way rich (12-13:1 afr) or way lean (16-18:1 afr).

thanks in advance.

[Darius]

It is still running off of the stock O2 sensor in closed-loop, correct? Sounds like the OEM O2 sensor might be crapping out.

[twisted99s10]

no, its running off the wideband o2. its a plx wideband o2, it has its own little control module that has a narrow band output. i suppose its possible that it is malfunctioning.

[lexrob]

I dont know much about plx but as far as accuracy AEM from everyone. After working with an lc-1 I completely agree. Not shur it thats like a handheld unit but grounding if its not i guess they are Really Really sensative to any elec. noise. I have no idea about nissans but hondas cut fuel when letting off the throttle and at rev limit causing a crazy lean spike.

[lexrob]

Sorry to add but unburnt fuel can also show up as a lean spike..... dont know if that could even be the case tho. Maybe ignition system again i dont even know it nissans have a control module my teg would randomly cut out. Got worse and worse and then wouldnt start so i fig. it out. "man that was annoying"

[kcsturbocustoms]

My rb did the same changed o2 sensor worked fine after.