MB

I'd say more likely the cat has collapsed.

Checking fuel trims not much use imo. You would need a decent scan tool for that and hard to diagnose much from it.

noodels

I would covert to wideband if replacing the primary sensor PLX DM6 Gen 4 the AFR gauge would come in useful,
though getting difficult to find at good £s

MB

Standard ECU can't interpret a 0-5v signal from a wideband unless it has a seperate 0-1v narrowband output.

starchland

Op has access to a scan tool it sounds so it's free why not. Stft/left can show if it's running rich or lean and important part of the process imo. Watch the Stft as you drive

GhostWKD

Sorry been crazy at work so slow on the update front.

I fitted a new front lambda sensor but sadly the car is still having a problem with its idle. The engine management light still comes on every now and then with a knock sensor warning.

Garage that helped me out with the lambda (was insanely rounded off) has suggested a vac leak somewhere.

Going to look at the stft (no idea what this is but I'll have a poke about) and see if that gives anything away.

The fun continues but before it does so I've picked up a nail in my tyre which needs looking at first

noodels

No point in this to use as an upgrade to convert to wideband,
If unless your primary is slow to react and replacement is required ?
Was thinking it would help sample times and correction of trim a little

nomadicS2k

Have you cleaned the IACV and the throttle body?
How old is the fuel?

GhostWKD

IACV I've cleaned, throttle body wise which bit would be the area to look at cleaning?

I've done about 6k miles since getting the car in Jan (It's my daily driver) and it's always had this slightly iffy idle although feels worse recently so not fuel related sadly.

nomadicS2k

Did the IACV clean do much? It should have made it a little more ...subtle.
You should be looking at cleaning the butterfly and the chamber where it sits. Mine was gunked up.
Mine still does stutter a little bit but it has an AEM v2 CAI - which I am contemplating of binning. My Lambda's just turned up from RokAuto so I will be fitting them next week.

GhostWKD

Sadly it did nothing, if anything it has made me contemplate replacing the IACV but I'm keen to check for vac leaks first