Splitpin

If your A/F correction is reading -25%, that means the ECU is actually removing fuel to try and lean off the mixture in response to the O2 sensor reading consistently high for an extended period of time. Given all you're reporting it sounds like the lambda sensor signal line is picking up a false voltage from somewhere, with the ECU taking out fuel as a result to the point where the mixture is becoming far too lean.

There's no way in a million years that a properly functioning setup should give a lambda sensor voltage of 1.0 volts, let alone above it - you could maybe see 0.93 to 0.95 on a rich car with a fresh sensor under full boost but anything over 1, especially on low throttle, suggests something's very wrong.

A dodgy O2 sensor would be unlikely to give these symptoms - normally when they go they read too low (and cause rich running) rather than the reverse.

Running with the O2 sensor disconnected shouldn't damage the engine but that won't be a permanent solution as your car almost certainly won't pass an MOT emissions test without it stabilising the mixture.

For what it's worth this'll be my last post on this thread, at least until/unless you have the car checked out properly. Given the scale of the (probably unmapped) mods it's impossible to know how to make sense of the data you've posted as I don't know (and can't tell) whether, for example, the MAF fluctuations you're seeing are "normal" within the context of those modifications.

Given the above it's impossible to add anything constructive here. If your car was standard, or we knew it had been mapped properly to start with, that's one thing as your log data has a definable context. Without it the figures lose a lot of their meaning.

As things stand the best thing I can suggest is that you take it to an experienced specialist or mapper, both to have what sounds like a closed loop fuelling issue checked out, and also to get (or make sure) it is running within a safe performance envelope for the modifications it's running.

scoobyboothy

iTrader: (1)

cheers for your input, I think now i've exhausted all areas that i can explore on my own, with the software I have (wish i had the full version of delta dash!!LOL), I wouldn't have got this far without your expertese, you should set your own site up "www.ask-subarusplitpin.co.uk" cos you're mountain of knowledge

I know I may have masked the problem at the mo, but at least I can drive it without it randomley loosing power

cheers splitpin