EML came on but car runs OK

[Tonycole]

Yellow engine light on but runs OK 

[Mike Percival]

I have the engine light on as well, the previous owner told me it's the oxygen sensor in the exhaust and it shouldn't affect the vehicle performance. To be honest I have no idea why such a sensor should be fitted anyway, unless it's to do with pollution levels.

At least the vehicle still runs OK.

[Jamie_uk]

Hesitant acceleration between 1500-2000rpm. Lower fuel economy. Rattling/whirring/grinding noise started while pulling away. 

All went away after changing my rear o2 sensor. Wish I’d done it sooner but one of them things you get round to and the car works so can’t be that bad….. if it happens again I’ll be doing it right away
 

Not a mechanic by any means but sure I read they are involved with air/fuel ratio and if left can lead to a screwed up engine. Was another topic on here about this, last thing said was they were told it would have been a lot more serious soon so assuming 

[Mike Percival]

How difficult is changing the sensor? I am fairly competent and don't mind getting my hands dirty!

[Jamie_uk]

Front or rear? Not sure if different years or models have a different lay out 

front sensor on mine I can see on the exhaust in between engine and radiator, haven’t changed that one but looks like the easier one since it’s literally in front of my eyes

 

rear sensor down the left side of the engine as you look at it, awkward Git of an angle, blew £30 on extension bars and long socket to beefcake it from above, not enough space to get socket on. Unamused. Ended up pulling all underside trims off driver side too went in through wheel well with adjustable spanner do or die style and cracked it off. Anger is the key. 

get one of the offset 22mm o2 sockets, get it from underneath with a ratchet (what I was originally going to do) access would have been a doddle. Mine was TIGHT, try penetrating fluid around the threads if can get near them, anything that helps it at all is a bonus