I had rough idling issues for a month or two with an error code consistently produced for the front lambda sensor (16514). I bought a Bosch replacement online & had my local friendly garage replace it for me just before Xmas.

However, the car is now back to running rough - scanning yesterday I got the error codes:

16514 (the front Oxygen sensor again!)

17544 System too Lean (I was getting this previously)

Plus some misfires:

16684

16686

16688

I don't know where to go from here...

Some ideas or things I have yet to do:

I still have the breather under the inlet manifold to check - although I doubt this would cause so many error codes?

I have replacement plugs & coils to fit - I guess I could check the wiring loom at same time

Unplug the MAF and see if it makes any difference

However, I get the feeling this might be an electrical issue - dodgy earth or something?

Any help or advice is gratefully received, as this is starting to be a pain! Thanks!

Sounds like coil packs or possibly the wiring loom to the coil packs if it's misfiring like that.

Also - did you get the garage to check the wiring to the front oxygen sensor when they replaced it? If that is broken then it may be underfueling because of the duff lambda readings which would also cause the misfires.

Get the new coils and plugs on and see if that helps, if it's still doing it then run it in the dark with the bonnet up and engine cover off and look for any arcing on the wiring loom to the coil packs.

thanks CE

Check if you have any leaks in your downpipe, back pressure sucking in fresh air WILL trigger a lean response code, which in turn will cause misfires from over fueling. Is it backfiring, popping/banging on the overun?? Also inspect (as best as you can) the exhaust manifold for cracks.

Steve

havent detected any over-run issues or noises.

Think my plan over the weekend will be to swap the plugs & coils along with the remaining breather under the manifold & see where I am.

Have you checked with a dealer ref coils?

Should get a new set under the recall.

Have you checked with a dealer ref coils?

Should get a new set under the recall.

I bought a set a while back, so have them ready to go

More than likely u have an air leak 9 times out of 10 a lean fault code indicates air leak the misfires etc can all be related to that

Steven