Got a bit of a basketcase here that I have mostly got dialled in now. It's an XH ute with a BF NA barra, it's turbo now but it's done this since i got it NA. It's manual, ecu has no speed signal connected currently.

I have the (stock) injectors dialled in pretty well, and the SD tables seem good, it hits its commanded AFR quite accurately.

For some reason though, when it's sitting idling, it'll be spot on, and all of a sudden it will go to +25 STFT and start commanding 0.71 lambda. It hits this no problem, but obviously it's rich as shit and i'm quite sure it's not supposed to do it. if i rev it it will generally sort it's shit out and idle back at a commanded .98 or thereabouts.

I've disabled the oxygen sensor, it still does it. disabled the cat over temp control, still does it. can anyone think of what may be making it do this? I'll post a tune file and a log later on, i'm at work now.

cheers for any help!