Running rich - how do I solve it?

So, today’s MOT revealed that my car’s hydrocarbons were too high.  Apparently this means it’s running too rich?

 

How do I sort this out please?

 

I removed the air filter and it then “passed” by the way. Cool

 

Would fitting a K&N his filter have the same effect?

 

Does anyone have any photos of how to fit the K&N to stop it rubbing on the engine/bodywork? And photos of an exhaust manifold heat shield please?

 

Thanks

You do not state whether you fitted a new air cleaner for test.If you did not buy a new one
buy one now of the same make and weigh them both,this will give you an idea of how much work
the original filter has done.
Regards Ian.

if its mk2 or mk2.5 the 3 pin thermo sensor under the oil has reduced emissions for me dozens of times. I actually proofed this more then once, byu failed MOT/NCT tests ,replaced sensor, passed straight away without any other work!!

Sounds interesting.
Where is the 3 pin sensor located please?, before I start to look “Under the oil” 

 

thanks

 

I actually just removed the cleaner filter completely.

I had previously cleaned it out with a very high pressure air jet, though it was fairly new looking anyway