Fault code P0172

P0172 bank 1 system too rich. Had this fault come up lately, after clearing it comes on after a day or 2 

My in tank fuel pump has been humming/ticking on idle for a while now so I presume its got something to do with it?

Also had a new 3" catback fitted lately, will this also throw the code up? Rosstech says its because the air/fuel ratio is out of balance 

My thoughts are that a new LPFP & a map tweak should cure this?

Any advice?

Its on a BWA engine