Engine management light on!!

[clio182rs]

Hi guys..
Driving my Clio 182 home, and the engine management light came on..
So I hooked it up to my cheap code reader, and it came up with a couple of issues..
So I took it to my local garage, who changed the front lamba , and turned the light off, but he's not convinced that was the problem..
He said.
Both lambas seemed ok, but he was getting negative fuel trim at idle, and the engine seemed to be hunting up and down...
The engine seems to be trying to reduce fuel but not able,
Could the pcv on the rocker cover be at fault??
Any of you guys any ideas what the solution could be??.
Thanks in advance..

 

[Touring_Rob]

Could be an injector (super common).

When mine started to fail it ran very rich for a while before tuning into a big misfire.

 

[SharpyClio]

The second one I get now and then it’s from the downstream o2 sensor. Won’t have an impact on the fuelling though. I had a an upstream o2 sensor failure that didn’t seem to show up on codes, replaced it and fixed all my fuelling issues.